EP0201788A2 - Apparatus for cutting and/or scoring paper webs - Google Patents

Abstract

Device for cutting and/or scoring cardboard or paper webs, with at least one rotatably mounted shaft which is driven by a rotary drive and on which is arranged at least one annular cutting or scoring tool, displaceable in the axial direction of the shaft, with a holding device which acts between the shaft and the tool and by means of which the tool is held in a desired axial position on the shaft, and with a positioning device by means of which the tool is displaced into a desired axial position on the shaft, the annular tool (4, 51) consisting at least partially of magnetic material, the shaft (1, 50) consisting of non-magnetic material, and there being arranged in the shaft (1, 50), preferably at equal intervals, a series of magnetic arrangements (3, 52) which interact magnetically with the tool (4, 51) and which retain it in an assumed position by magnetic attraction.

Description

Devices for the longitudinal cutting and longitudinal creasing of paper or cardboard webs normally have at least one pair of rollers with annular cutting or creasing tools in order to cut or creasing the continuous web in the longitudinal direction. Depending on the order, the position of the tools on the shafts must be readjusted. For this purpose, the tools can be clamped on the shafts and can be detached again if necessary. The loosening and clamping of the tools should, if possible, be carried out automatically. In this context, it is known to design the waves as expanding waves, which are expanded radially with the aid of a pressure medium - (DE-OS 22 50 508). It is also known to arrange expandable hoses in the grooves of the shafts in order to clamp the tools. The grooves are either ring-shaped or helical. Finally, it is also known to arrange several jaws in the tool carrier and to bring the jaws into engagement with the shaft with the help of one or more pressure hoses (DE-OS 20 59 970).

The positioning of the ring-shaped tools on the shaft should also be carried out automatically if possible. It is known to do this with the aid of pawls or the like, which are arranged on a threaded spindle parallel to the tool shaft and can be brought into engagement with the tools in order to shift them by a certain amount on the tool shaft (DE-PS 25 26 599). In the known device, initiators are also provided to report the positions of the tools on the tool shaft or to control the positioning process.

The loosening and re-tightening as well as the positioning of the tools requires a certain amount of time in the known devices. The invention has for its object to provide a device for cutting and / or creasing cardboard or paper webs with which the tightening or loosening of the tools from the tool shaft and possibly also the positioning can be accelerated. This object is achieved in that the ring-shaped tool consists at least partially of magnetic material, the shaft consists of a non-magnetic material and a number of magnet arrangements, preferably at equal intervals, are arranged in the shaft, which interact magnetically with the tool and it hold in an occupied position by magnetic attraction.

The basic idea of the invention is to generate a magnetic field on the shaft at a desired axial circumferential location, which holds the tool in the assumed position. The magnetic holding force must be so great that the lateral forces that occur during operation do not lead to a displacement of the tool. Usually two knives or creasing tools work together. In particular, the knives can be biased against one another during magnetic holding, so that the certainty that the position assumed remains in place is increased.

According to an embodiment of the invention, individual electromagnet arrangements are arranged in the shaft, which can optionally be connected to a current source outside the shaft. When using direct current, the tools can, at least partially, consist of steel or iron, and thus develop magnetic behavior in the case of a direct field. However, the electromagnets can also be operated with alternating current. In this case, a current can be generated in a ring-shaped conductor on the tool or tool carrier, which in turn results in a magnetic field that interacts with the magnetic field of the electromagnet (if tools are mentioned below, the arrangement of tool carriers plus is in principle actual tool). In this case, at least a part of the tool carrier made of layered magnetic material in the form of a laminated core is necessary in order to obtain a clearly directed magnetic flow in relation to the conductor.

The axial extent of a magnet arrangement in the shaft cannot be chosen to be arbitrarily small. The tools should take any position on the shaft if possible. In order that this can be achieved with the aid of the magnet arrangements, one embodiment of the invention provides that the magnet arrangements are arranged in such a way that their fields overlap on the outside of the shaft. By amplifying, compensating or partially compensating the magnetic fields of individual adjacent magnet arrangements, a maximum magnetic holding force can be achieved at any circumferential location in the axial direction, so that the tool is effectively held after the positioning has been carried out.

With an appropriate arrangement, all electromagnets can be connected to the power source at the same time, if this does not lead to a subsequent adjustment of the tool. In this case, the power source located outside the shaft only needs to be coupled to the shaft via a pair of slip rings. Each magnet arrangement can optionally be assigned its own switch in the shaft, by means of which the magnet arrangements can be connected to the current source. In the shaft or outside, a control device is provided for the optional connection of the electromagnet arrangements to the power source. The current source lying outside the shaft is then also connected to the shaft via slip rings. The switches located within the shaft are all coupled to the terminals connected to the slip rings. If a switch is closed, it connects the associated electromagnet arrangement to the power source. The switches can be controlled contactless or contact-based. In the latter case, an additional galvanic connection must be created from the inside of the shaft to the outside via slip rings. In order to achieve a desired magnetic field distribution on the outside of the shaft, the current flowing into a magnet arrangement can be changed if possible.

In the device described above, the tool is only held magnetically. A further embodiment of the invention provides that the tool supports at least one shoe which is radially movable with respect to the shaft axis, which is designed as an armature and which can be brought into engagement with the shaft by the magnetic field of one or more magnet arrangements. In this embodiment, all magnet arrangements in the shaft can be switched on simultaneously for clamping the tool. A targeted control of individual magnet arrangements is therefore not necessary. The use of one or more of such shoes for the tool has the advantage that the tool can be relatively easily slidably mounted on the shaft.

In the embodiments described above, the magnet arrangements serve only to hold the tools in predetermined positions on the shaft. The positioning is carried out in any known manner. In the case of the invention, however, it was recognized that an arrangement comprising a plurality of electromagnets in the shaft can also be used for positioning. In this context, an embodiment of the invention provides that the magnet arrangements are arranged and can be connected to the power source via a control device such that a linear motor is formed in which the shaft with the magnet arrangements is the stator and the tool is the rotor.

The basic principle of an electric linear motor is that a series of magnetic poles is provided in a linear arrangement and a rotor interacts with the magnetic poles, which rotor is carried along by a magnetic field generated by the individual poles. In the case of linear motors, a distinction is made between AC and DC linear motors. Both are applicable to the present case. In the case of the direct current linear motor, the field of excitation is changed in terms of time and location. As a result, a tool captured by the magnetic field of a pole can be taken along and moved on the shaft. Once it has reached the desired position, the excitation of the magnetic field is ended. A linear motor of this type can be used directly for positioning without the need for appropriate feedback. Alternatively, position transmitters can also be provided, which are activated in accordance with the desired position of the tool on the shaft and cause de-excitation of the electromagnet arrangements as soon as the tool has reached the desired position. With the help of alternating current, a moving linear field can be generated accordingly. As is known per se, this principle corresponds to the asynchronous motor developed in one plane, the tool forming the squirrel-cage rotor in the present case. For this purpose, the tool must be provided with a laminated core in order, as already explained above, to obtain a clearly directed flow and a conclusion for the magnetic field.

In the last-described embodiment, the individual magnet arrangements serve as positioning devices for one or more tools. The magnet arrangements can be controlled in the manner described above. The clamping of the tools on the shaft can, however, take place in a conventional manner, for example with the aid of the pressure hoses mentioned embedded in the shaft or by expanding hoses in the tools. According to a further embodiment of the invention, when the shaft is designed as a linear motor, the tool is simultaneously magnetically held at a standstill. After the tool has reached the desired point through the linear motor. the field remains in the area of this position in order to generate a sufficient magnetic holding force.

So that the tools only have to be held in the axial direction, but not in the circumferential direction, the tools are preferably arranged in a rotationally fixed manner on the shaft.

The shaft can have a continuous groove or a continuous strip parallel to this axis, which cooperates with a corresponding projection or corresponding groove on the tool.

Another alternative is that the pawls disclosed in DE-PS 25 26 599 are placed in the tool shaft. The tool shaft can have one or more pawls which are mounted in corresponding axially parallel slots and which are connected to the rotor of a linear motor. The pawls can also be used to secure the axial position of the tools. Alternatively, the pawls can also be moved into the tool shaft when the tools have reached their position. The tools can then be clamped onto the shaft in another way, for example according to one of the embodiments described above.

• Fig. 1 zeigt den Schnitt durch eine Längsschneid-und Rillmaschine herkömmlicher Bauart.
• Fig. 2 zeigt schematisch eine Werkzeugwelle mit zwei ringförmigen Werkzeugen.
• Fig. 3 zeigt schematisch die Anordnung von Magnetanordnungen in der Werkzeugwelle nach Fig. 2.
• Fig. 4 zeigt einen Schnitt durch die Anordnung nach Fig. 3 entlang der Linie 4-4.
• Fig. 5 zeigt einen Schnitt durch eine Werkzeugwelle in schematischer Darstellung mit einer anderen Magnetanordnung.
• Fig. 6 zeigt schematisch Positionsgeber für Werkzeuge auf einer Werkzeugwelle.

The invention is explained in more detail below with reference to drawings.

• 1 shows the section through a slitting and creasing machine of conventional design.
• Fig. 2 shows schematically a tool shaft with two ring-shaped tools.
• FIG. 3 schematically shows the arrangement of magnet arrangements in the tool shaft according to FIG. 2.
• FIG. 4 shows a section through the arrangement according to FIG. 3 along the line 4-4.
• Fig. 5 shows a section through a tool shaft in a schematic representation with another magnet arrangement.
• Fig. 6 shows schematically position transmitter for tools on a tool shaft.

Before going into the details shown in the drawings, it should be stated that each of the features described is of importance for the invention, either individually or in conjunction with features of the claims.

1 shows a frame 30 of a longitudinal cutting and creasing machine, which supports two tool shafts 31, 32 in a known manner (details are not discussed here. Reference is made, for example, to the detailed description of DE-PS 25 26 599). . The tool shafts 31, 32 support pairs of tools from the upper tool 33 and lower tool 34, which in the released state can be moved along the axis. An adjustment spindle 35 is mounted in the frame 30 above the upper tool shaft 31. A second adjusting spindle 36 is mounted in the frame 30 below the lower tool shaft 32. The shafts 31, 32 are driven synchronously by the motor 37 via a gear 38 and a gear chain 39. The adjusting spindles 35, 36 are driven synchronously by the motor 40 via a gear 41 and a gear chain 42. Slides 43 and 44 are seated on the adjusting spindles 35, 36 and are provided with a pawl 45 and 46, respectively. The pawl 45 or 46 can either be engaged or disengaged from a tool 33, 34. With the help of the slide 43, 44, each tool 33, 34 can be brought into any position on the tool shaft 31, 32. During operation, the pawls 45, 46 are disengaged from the tools 33, 34.

FIG. 2 shows a tool shaft 1, which corresponds approximately to the tool shaft 31 or 32 according to FIG. 1. It is formed in the form of a ring cylinder and consists of a non-magnetic material, for example a hard aluminum or brass alloy, or of a non-magnetic steel. In FIG. 2, two tools 4 are also arranged extremely schematically, which can correspond to tools 33 and 34 according to FIG. 1. Fig. 3 shows in longitudinal section a part of the shaft of Fig. 2. It can be seen that an electro-magnet arrangement 3 is arranged within the shaft, which has two spaced disks 7, 8 made of magnetic material, which is arranged on both sides of a core 10 to which is wrapped around a winding 11. The discs 7, 8 are tapered at the ends, so that the discs 7, 8 approach radially outwards. In the shaft 1 a number of such magnet arrangements 3 is arranged close to each other. These magnet arrangements 3 can optionally be magnetically insulated from one another. The winding 11 is connected via two conductors 12, 13 to slip rings 14, 15 on the shaft 1, which are arranged concentrically to the axis 2 of the shaft 1 and rotate with it. Brushes 16, 17 interact with the slip rings 14, 15. Lines 18, 19 connect the brushes 16, 17 to a direct current source 20, a switch 21 being arranged in line 19.

If the switch 21 is closed, the magnet arrangement 3 is excited and a magnetic field is formed, the direction of which on the outer circumference of the shaft 1 in the region of the tool 4 runs approximately axially parallel. Since the tool 4 at at least partially consists of magnetic material, it is held in the position shown in FIG. 3. It should be noted that the air gap 9 between the disks 7, 8 must be larger than the air gap between the individual disks 7, 8 and the tool 4. In the illustration according to FIG. 3, all magnet arrangements 3 are parallel or in series with the power source 19 connected. If the magnet arrangements 3 are to be switched on selectively, each magnet arrangement 3 must be assigned its own switch. In the event that the switches are arranged outside the shaft 1, a slip ring pair must be provided for each magnet arrangement 3. It is therefore preferable to arrange the switches within the shaft and to switch them on from the outside without contact or galvanically using appropriate control commands.

From Fig. 4 it can be seen that the shaft 1 has three grooves 23, 24, 25 equally spaced in the circumferential direction, which are formed on the circumference of the shaft 1 and extend axially parallel. The tool 4 has corresponding projections 26, 27, 28 which cooperate with the grooves 23, 24, 25 and secure the tool against rotation.

A tool shaft 50 is shown in section in FIG. 5, which corresponds, for example, to the tool shaft 31 or 32 according to FIG. 1. A single tool 51 is arranged on the shaft, for example corresponding to tool 33 or 34 according to FIG. 1. In the tubular shaft made of non-magnetic material, a plurality of electromagnet arrangements 52 are arranged tightly packed next to one another.

Each magnet arrangement has a cylindrical ring 53 made of magnetic material, into which a rectangular groove 54 is formed on the circumference. An electrically insulated conductor 45 of rectangular cross section is arranged in the groove 54. Thin disks 56 made of non-magnetic material are arranged between the disks 53. The conductors 55 generate a field which surrounds the conductors in a circle and pass through the tool 51 accordingly. If this is magnetic, it is held in the assumed position. One or more radially movably mounted shoes can be arranged in the tool 51, as shown in dashed lines at 57. When a magnet arrangement 52 is excited, the shoe 57 is pressed in the direction of the circumference of the shaft 50 in order to firmly clamp the tool 51.

The magnet arrangements 3 according to FIG. 3 or 52 according to FIG. 5 can also be used to generate a magnetic traveling field which moves axially parallel on the outside of the shaft. In this case, the series arrangement of the magnet arrangements 3 or 52 is the stator of a linear motor, while the tools form the rotor. The magnet arrangements 3, 52 can therefore alternatively also be used to position the tools 4 or 51, as a modification of the tool positioning, as shown in FIG. 1. The Unearmotor formed in this way, however, can also generate sufficient magnetic holding force in addition to the positioning to hold the tools in the assumed position. Position sensors can be provided for controlling and / or monitoring the position of the tools. In Fig. 6, three position sensors 48 are shown, which with a suitable control or. Monitoring circuit (not shown) are connected. The position of the pawl 45 for adjusting the tools 33 is to be determined with them so that the positioning can be carried out or monitored.

Claims (8)

1. Device for cutting and / or creasing cardboard or paper webs with at least one rotatably mounted shaft driven by a rotary drive, on which at least one annular tool for cutting or creasing is arranged, which is displaceable in the axial direction of the shaft, one between the shaft and Tool-acting holding device with which the tool is held in a desired axial position on the shaft and a positioning device with which the tool is displaced in a desired axial position on the shaft, characterized in that the annular tool (4, 51) consists at least partially of magnetic material, the shaft (1, 50) consists of non-magnetic material and in the shaft (1, 50) a number of magnet arrangements (3, 52), preferably at equal intervals, are arranged, which are magnetically connected to the tool (4, 51) interact and hold it in an assumed position by magnetic attraction. 2. Device according to claim 1, characterized in that individual electromagnet assemblies (3, 52) are arranged in the shaft, which can be optionally connected to a power source (20) outside the shaft (1). 3. Apparatus according to claim 2, characterized in that the magnet arrangements are arranged so that their fields on the outside overlap the wave. 4. Apparatus according to claim 2 or 3, characterized in that each magnet arrangement is assigned its own switch in the shaft, through which the magnet arrangements can be connected to the power source and is provided in the shaft or outside the control device for selective excitation of the electromagnet arrangements. 5. The device according to claim 4, characterized in that the switchable to the individual magnet arrangements current of the current source is variable. 6. Device according to one of claims 1 to 5, characterized in that the tool (51) supports at least one radially movable shoe (57) with respect to the shaft axis, which is designed as an armature and through the magnetic field of one or more magnet arrangements (52) in Engagement with the shaft (50) can be brought. 7. The device in particular according to one of claims 1 to 6, characterized in that the magnet arrangements are arranged and can be connected to the power source via a control device such that a linear motor is formed as the positioning device, in which the shaft with the magnet arrangements of the stator and the Tool is the runner. 8. The device according to claim 7, characterized in that the tool is held magnetically at a standstill.

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