WO1999058322A1

WO1999058322A1 - Combined slitting and creasing unit for carton blank production

Info

Publication number: WO1999058322A1
Application number: PCT/SE1999/000698
Authority: WO
Inventors: Jan Andréasson; Bengt ÅSBERG
Original assignee: Emba Machinery Ab
Priority date: 1998-04-29
Filing date: 1999-04-28
Publication date: 1999-11-18
Also published as: SE9801510D0; SE9801510L; SE514186C2

Abstract

Combined slitting and creasing unit forming part of a machine for production of carton blanks, in particular blanks made of corrugated cardboard. The unit comprises upper and lower slitting wheels interacting in pairs and upper and lower creasing wheels (28) interacting in pairs. At least one upper slitting wheel and one upper creasing wheel are mounted in a common upper stand unit and at least one lower slitting wheel and one lower creasing wheel are mounted in a common lower stand unit (4). At least one of the creasing wheels (28) in each pair is provided with a creasing rim (32) and is displaceable in the lateral direction relative to the associated stand unit (4) and slitting wheels mounted therein. The creasing wheel (28) which is displaceable in the lateral direction is in thread engagement (53) with an additional wheel (44) which is mounted concentrically with the creasing wheel and in the stand unit (4) of the latter and is usually driven synchronously with the creasing wheel. Means (52) are arranged for temporarily changing the speed of rotation of one of these two wheels (28, 44) relative to the other, the mutually engaging threads (53) of the wheels causing the creasing wheel (28) to be displaced in the lateral direction relative to the stand unit (4) and slitting wheels mounted therein.

Description

COMBINED SLITTING AND CREASING UNIT FOR CARTON BLANK

PRODUCTION

The present invention relates to a combined slitting and creasing unit forming part of a machine for production of carton blanks, in particular blanks made of cardboard or corrugated cardboard, which unit comprises upper and lower slitting wheels interacting in pairs and upper and lower creasing wheels interacting in pairs, at least one upper slitting wheel and one upper creasing wheel being mounted in a common upper stand unit and at least one lower slitting wheel and one lower creasing wheel being mounted in a common lower stand unit , and at least one of the creasing wheels in each pair being provided with a creasing rim, which creasing wheel is displaceable in the lateral direction relative to the associated stand unit and slitting wheels mounted therein, and members for feeding plane carton blanks between the wheel pairs .

Combined slitting and creasing units of this type are used for providing carton blanks with slits and creases which are required for the subsequent erection of the blank to form a carton. In this connection, the unit usually comprises a number of slitting-wheel pairs arranged one after the other and beside one another in order to produce both slits which are open towards the front and, respectively, rear edges of the blanks and slits which are separated in the lateral direction. In this connection, the creasing wheels are usually intended to produce a crease between and essentially in line with such slits.

The slitting wheels and creasing wheels arranged on a common stand unit are displaced as a unit together with the associated stand unit in the lateral direction in relation to the direction of feed of the blanks in order to produce slits and creases in the desired positions on a carton blank. In this connection, there may sometimes be a requirement to be capable of performing small - 2 - displacements of the creasing wheel in relation to the slitting wheels for fine adjustment of the positioning of the crease relative to the slit. In this way, it is possible inter alia to determine with which side of a slit the crease is to run in line. This may be important during the final folding of the carton blank. Furthermore, there may be a requirement to adjust the position of the crease in relation to the channels in a corrugated cardboard blank.

In previous arrangements, it has been relatively complicated and time-consuming to effect a relative displacement between a creasing wheel and a slitting wheel. It has been necessary for inter alia the whole machine to be stopped in connection with the performance of such an adjustment. As all operational stoppages reduce the production, these involve increased production costs for the blanks .

The main object of the present invention is to produce a combined slitting and creasing unit, in which a creasing wheel can be laterally adjusted simply relative to the slitting wheel.

Another object is to produce a unit in which such an adjustment can take place during operation.

These objects are achieved according to the present invention by means of a combined slitting and creasing unit of the type indicated in the first paragraph, which is characterized in that the creasing wheel which is displaceable in the lateral direction is in thread engagement with an additional wheel which is mounted concentrically with the creasing wheel in the stand unit of the latter and is usually driven synchronously with the creasing wheel, and in that means are arranged for temporarily changing the speed of rotation of one of these two wheels relative to the other, the mutually engaging threads of the wheels causing the creasing wheel - 3 - to be displaced in the lateral direction relative to the stand unit and slitting wheels mounted therein.

This arrangement thus makes it possible to effect the desired lateral displacement between a creasing wheel and a slitting wheel during operation by means of a temporary change in speed of a drive shaft . The creasing wheel can be mounted displaceably on a drive shaft or alternatively the drive shaft can be mounted displaceably.

In a preferred embodiment, the additional wheel mounted concentrically with the creasing wheel is driven by another driven wheel which is in turn driven by the same drive source as the drive shaft of the creasing wheel . In this connection, a gear arrangement in the form of a so- called register can suitably be coupled in between the drive source and one of the drive shafts of these wheels for temporarily changing the speeds of rotation of the wheels in relation to one another.

The creasing wheel is suitably made with a hub portion which projects into a sleeve-shaped hub portion of the additional wheel mounted concentrically with the creasing wheel, these two hub portions being made with interacting threads. Parts of these hub portions, which are not provided with threads, are in this connection made with a plain bearing.

The invention will be described in greater detail below with reference to the embodiment shown by way of example in the appended drawings .

Fig. 1 is a diagrammatic perspective view of a combined slitting and creasing unit according to the invention.

Fig. 2 is a side view of a pair of stand yokes with associated working wheels in the unit in Fig. 1.

Figs 3 and 4 show the blank before and, respectively, - 4 - after working in a slitting unit according to the invention.

Fig. 5 is a cross-sectional view through a part of a lower stand yoke with the associated creasing wheel.

Fig. 6 shows the creasing wheel in Fig. 5 after a certain degree of displacement relative to the stand yoke.

In Figs 1 and 2, 1 indicates a conveyor track of optional type for feeding in plane blanks made of, for example, corrugated cardboard for working of these in a slitting unit 2 according to the present invention. The slitting unit comprises a number, four in the example shown, of pairs of upper and lower stand yokes 3 and 4 respectively located side by side, of which the upper yokes have been indicated only by means of dot/dash lines in Fig. 1. Mounted in each yoke are a number of working wheels one following another, the wheels mounted in the lower and, respectively, the upper yokes interacting in pairs to work a blank which passes between the wheels.

In the embodiment shown, the lower yokes 4 are made in the form of suction boxes with an internal negative pressure. To this end, the yokes have been connected to a vacuum blower or another vacuum source via a line 5. Each yoke 4 is provided with a conveyor belt 6 which runs around the yoke and is provided with a number of through- openings. At least the upper edge surfaces of the yokes 4, which surfaces interact with the belts 6, are made with openings so that the negative pressure in the suction boxes is conveyed via the openings in the belts 6 to produce a suction effect on a carton blank supported by the belts. Both the belts 6 and the various working wheels are driven by external drive sources by means of splined shafts 7 and, respectively, 8 which can be separated from the yokes or the working wheels so that the vacuum belts 6 can be mounted on the respective yoke 4 from the side. The yokes 4 thus perform two functions, on the one hand as stands for the working wheels and on the other hand as suction boxes for the vacuum belts 6.

The yokes 3 and 4 are suspended on transverse beams 9 via linear bearings 35, see Fig. 2, which allows the yokes to be displaced in the lateral direction relative to the direction of feed of the blanks for adaptation of the positions of the slits and the creases depending inter alia on the size of the blanks. In this connection, each pair of yokes can be displaced individually relative to the other yoke pairs. By means of the linear bearings 35, fine adjustment of the positions of the yokes is also possible, so that, for example, slits and creases run in the desired manner, for example in relation to the channels in a corrugated cardboard blank.

The slitting unit shown thus makes it possible for carton blanks to be fed through the various wheel pairs while they are held orientated exactly correctly on account of being fixed on the vacuum belts 6. This means inter alia that the wheels do not bring about any undesirable compression of the blanks or smearing of undried ink, which can occur in conventional slitting units in which the working wheels are also used as feed wheels for the blanks . Nor do the positions of the wheels in the respective pairs have to be adapted depending on the thickness of the blanks, and the cutting point can be adjusted so that it is located in the lower plane of the blanks .

The slitting unit shown in Figs 1 and 2 is intended to work the blanks 10 of the type illustrated in Fig. 3. In a preceding work station, the blanks have been provided with transverse creases 11 which may be required. In the case of corrugated cardboard blanks, the edge parts of the blanks are worked first by means of pairs of so- called crushing wheels 12. As has been indicated in connection with the upper crushing wheel 12 in Fig. 2, this is connected to an eccentric arrangement 13 which - 6 - can be used to adjust the final thickness of the edge parts of the blanks . The crushing wheels are driven by gear wheels inside the yokes. The left edge of the blank 10 shown in Fig. 3 is then worked by two cutting wheel pairs 14 which cut out a gluing flap 15 in the blank, see Fig. 4.

The right edge of the blank in Fig. 3 is trimmed by means of a wheel pair 16 which is preceded by a wheel pair 17 which serves as a so-called trimming crusher and cuts off the strip which is separated by the wheels 16 in short pieces. The upper wheel in the wheel pair 17 is provided with transverse knives 18 while the lower wheel is made with a stay pad. The wheels 16 have interacting trimming knives 20, 21.

To produce the three rearwardly open slits 22 and, respectively, the three forwardly open slits 23 in the blank 10, see Fig. 4, use is made of three first 24 and three second 25 pairs of slitting wheels. In this connection, the upper wheel in each pair is provided with a knife 26 which runs over a length of the periphery of the wheel corresponding to the length of the desired slit in the blank 10. The lower wheel in each slitting-wheel pair is made with a corresponding slot 34 for receiving the knife 26.

For the erection of the blank shown in Fig. 4 to form a carton, the blank must also be provided with longitudinal creases 27 between the slits 22 and 23. To this end, the slitting unit in Figs 1 and 2 is completed by four pairs of creasing wheels 28. Each of the upper creasing wheels is connected to an eccentric arrangement 29 driven by a drive shaft 30 via a gear wheel 31. The eccentric arrangement 29 is used to adjust the contact pressure of the creasing wheels against the blank passing through. The creasing wheels are driven via gear wheels inside the yokes. The slitting unit described above thus produces a carton blank according to Fig. 4 which is then conveyed to a work station in which the necessary handle openings are punched out in the blank.

Fig. 5 shows one of the lower yokes 4 with the associated creasing wheel 28 which is driven by a shaft 8. It can be seen that the yoke 4 is made in the form of a suction box with openings 13 in its upper edge surface. These openings interact with openings in the vacuum belt 6 running over them to secure a blank. In the yoke 4, two lower slitting wheels are also mounted in front of the creasing wheel 28, seen in the direction of feed of the blanks .

Along its periphery, the lower creasing wheel 28 is provided with a creasing rim 32 which interacts with a stay pad 33 of an upper creasing wheel to produce a longitudinal crease on the underside of a blank which is fed by the vacuum belt 6 between the creasing wheel 28 with the rim 32 and the stay pad 33 of the upper creasing wheel.

The crease 27 produced by the rim is to run essentially in line with the slits 22, 23 in the blank, see Fig. 4.

Depending on how the blank is to be folded, it may be desirable to be capable of adjusting the position of the creasing wheel 28 so that the crease 27 produced runs in prolongation of one side or the other of the slits 22 and 23. Furthermore, it may be desirable to adjust the position of the crease in relation to the channels in a corrugated cardboard blank.

In the embodiment shown, the lower creasing wheel 28 is in this connection made with a hub portion 42 which projects into a sleeve-shaped hub portion 43 of a gear wheel 44 which is mounted in the yoke 4 by means of roller bearings 45. The gear wheel 44 is driven by an - 8 - additional gear wheel 46 which is in thread engagement with the wheel 44 and is driven by a shaft 47.

The shafts 47 and 8 are driven synchronously with one another but in different directions by a common motor 48 which to this end drives a gear wheel 49 which is in tooth engagement with another gear wheel 50 which drives the shaft 8 via a register 52. The register 52 normally has a transmission ratio of 1:1 which means that the creasing wheel 28 and the gear wheel 43 are driven synchronously with one another in the same direction and at exactly the same speed.

The hub portion 42 is provided with a thread 53 which is in thread engagement with a corresponding thread on the hub portion 42 of the creasing wheel 28. 54 indicates a plain bearing between the hub portions 42 and 43.

If it is desired to adjust the position of the lower creasing wheel 28 in the lateral direction in relation to the yoke 4 and the slitting wheels supported by the latter in order to adjust the position of the crease in relation to the slits, a signal is supplied to the register 52. In this way, the transmission ratio of the register 52 can be changed for a short period of time so that the speed of rotation of the shaft 8 is increased or decreased in relation to the speed of rotation of the shaft 47. This means that the hub portions 42 and 43 rotate at slightly different speeds during this time. The thread 53 then causes the hub portions to be displaced slightly in relation to one another, the position of the creasing wheel 28 also being changed in relation to the slitting wheels mounted on the yoke.

When the necessary adjustment has been performed, the register 52 returns to working with the transmission ratio of 1:1 and the creasing wheel 28 will produce a crease in the blanks in the new position, see Fig. 6. The upper creasing wheel with the stay pad 41 does not - 9 - usually need to be displaced. If so desired, however, the upper creasing wheel can of course be displaced in a corresponding manner.

Instead of arranging the register 52 between the drive wheel 50 and the shaft 8, it can just as well be arranged between the drive wheel 49 and the shaft 47. In both cases, it is possible to adjust the position of the creasing wheel 28 without stopping the operation of the arrangement .

The invention has been described above in connection with the exemplary embodiment shown in the drawings. However, it may be varied in a number of respects within the scope of the patent claims. For example, the speeds of the drive shafts can be varied in a manner other than by using a register. Furthermore, the wheel 44 provided with the hub 43 can be driven directly by a drive shaft or via, for example, a chain or a toothed belt. If necessary, for example for reasons of space, the gear wheel 46 can of course be driven by an additional gear wheel or by means of a chain or a toothed belt. Those parts of the creasing wheel 28 and the extra wheel 44 with interacting teeth can be made in any manner, provided that a speed difference between the wheels brings about the desired displacement of the creasing wheel relative to the slitting wheels. If so desired, the arrangement described above can of course be used to displace the slitting wheels relative to the creasing wheel .

Claims

- 10 -PATENT CLAIMS

1. Combined slitting and creasing unit forming part of a machine for production of carton blanks, in particular blanks made of cardboard or corrugated cardboard, which unit comprises upper and lower slitting wheels (24) interacting in pairs and upper and lower creasing wheels (28) interacting in pairs, at least one upper slitting wheel and one upper creasing wheel being mounted in a common upper stand unit (3) and at least one lower slitting wheel and one lower creasing wheel being mounted in a common lower stand unit (4) , and at least one of the creasing wheels (28) in each pair being provided with a creasing rim (32) , which wheel is displaceable in the lateral direction relative to the associated stand unit (4) and slitting wheels (24) mounted therein, and members (6) for feeding plane carton blanks (10) between the wheel pairs, characterized in that the creasing wheel (28) which is displaceable in the lateral direction is in thread engagement (53) with an additional wheel (44) which is mounted concentrically with the creasing wheel in the stand unit (4) of the latter and is usually driven synchronously with the creasing wheel, and in that means (52) are arranged for temporarily changing the speed of rotation of one of these two wheels (28, 44) relative to the other, the mutually engaging threads (53) of the wheels causing the creasing wheel (28) to be displaced in the lateral direction relative to the stand unit (4) and slitting wheels (24) mounted therein.

2. Unit according to Claim 1, characterized in that the creasing wheel (28) is mounted displaceably on an associated drive shaft (8).

3. Unit according to Claim 1, characterized in that the creasing wheel (8) is driven by an axially displaceable drive shaft (8) . - 11 -

4. Unit according to any one of Claims 1-3, characterized in that the additional wheel (44) mounted concentrically with the creasing wheel (28) is driven by another driven wheel (46) , and in that this wheel is driven by the same drive source (48) as the shaft (8) of the creasing wheel.

5. Unit according to Claim 4, characterized in that the wheel (44) mounted concentrically with the creasing wheel (28) is driven via tooth engagement with said driven wheel (46) .

6. Unit according to Claim 4 or 5 , characterized by a gear arrangement (52) which can be temporarily coupled in between the drive source (48) and the shaft (8) of the creasing wheel or said driven wheel (46) .

7. Unit according to Claim 6, characterized in that said gear arrangement (52) which can be temporarily coupled in comprises a so-called register.

8. Unit according to any one of Claims 1-7, characterized in that the creasing wheel (28) is made with a hub portion (42) which projects into a sleeve- shaped hub portion (43) of said additional wheel (44) mounted concentrically with the creasing wheel, and in that said hub portions are made with interacting threads (53) .

9. Unit according to Claim 8, characterized in that a plain bearing (54) is arranged between said hub portions (42, 43) over parts of these which are not provided with threads.