FOLDING DEVICE COMPRISING UPSTREAM OR DOWNSTREAM BLADE SHAFTS OR COMPARABLE TOOL SHAFTS

Abstract

In a device (10) for folding a paper web (28) comprising a pair of tool shafts (24, 26) carrying circular knives (70, 74) which pair is arranged upstream or downstream of its folding rollers (16, 18, 20, 22), the circular knives (70, 74) and/or the transport roller units (40, 50) can be rotatively driven for transporting the paper web at the same web running speed in the region of the tool shafts (24, 26) and in the region of the folding rollers such that the speed components of the circular knives (70, 74) in the web running direction are at least not lower, preferably higher than the web running speed of the paper web (28).

Description

TECHNICAL FIELD

The invention relates to a device for automatically folding paper webs. Upstream or downstream of such folding devices using the knife folding or the buckle folding technology there are longitudinal cutting means provided, for example, for bringing an already folded sheet or a sheet to be folded subsequently into the correct width by cutting off longitudinal margins or for cutting the product into a plurality of panels.

PRIOR ART

It is known to equip folding devices, such as, for example, buckle folding devices, with upstream or downstream tool shafts. These tool shafts can be equipped for longitudinal cutting, but also for perforating or creasing. For longitudinal cutting, upper and lower knives can be used which are supported fixedly against rotation on a corresponding upper and lower shaft, respectively. By means of such circular knives, two of which are cooperating in each case, the web can be cut in one shearing cut in the longitudinal direction, i.e. in the running direction of the web. Due to manufacturing tolerances of the cutting knives it is very difficult to bring the cutting gap between the respective upper and lower knives to zero, if possible, in order to achieve the highest cutting quality possible. It is known to axially displace the circular knives on the respective upper or lower knife shaft in order to adjust the width of the cutting gap. In order to avoid undesired bulging of the web, the conveying speed of the paper web between the tool shafts and the folding shafts of the folding device must be exactly the same. The shearing-cut cutting principle implies that the diameters of the upper and lower knives are somewhat larger than the transport rollers which are provided on each cutting shaft and convey the paper web between them. However, due to this overlap, the cutting knives have—in spite of their higher circumferential speed due to their larger diameters—at the cutting point a somewhat lower speed component in the running direction than the paper web. In the case of a shearing cut, this leads to the fact that the paper web is kind of pulled through the cutting knives, which leads to a very bad cutting quality especially in the case of thin paper.

DESCRIPTION OF THE INVENTION

The object underlying the invention is, starting from the prior art as mentioned above, to form the tool shafts, such as, in particular, knife shafts, which are arranged upstream or downstream in folding devices, such that a shearing cut of the highest quality possible or a longitudinal processing comparable thereto is achieved.

This invention is described in independent claim 1, 11 or 13. Appropriate further developments of the invention are the subject-matter of the respective dependent claims relating thereto.

According to a first embodiment of the invention, the lower circular knife is, for example, supported in a freely movable manner on its knife shaft, while the associated upper circular knife is supported fixedly against rotation on its upper shaft. The lower, rotatively driven knife shaft is connected directly or indirectly through a transmission to the upper shaft such that the upper knife shaft is given a comparably higher rotational speed. This can also be achieved by a further own drive for the upper knife shaft. This higher rotational speed of the upper shaft results in the fact that the upper circular knife has a correspondingly high rotational speed. By laying the upper circular knife against the lower circular knife this high rotational speed can be transferred to the lower circular knife supported in a freely rotatable manner on its lower shaft. In order to achieve this, the lower circular knife can also be laid against the upper circular knife. In this way, it is guaranteed that the two cutting knives in the cutting point with the paper web have a higher speed component in the running direction of the web than the web itself, so that a shearing cut of high quality can be produced.

In order to guarantee an equally high web speed between the tool shafts, as, in particular, the knife shafts and the folding shafts of the folding device, further provisions can be made to arrange the transport rollers fixedly against rotation on the tool shaft on which the circular knife is supported in a freely rotatable manner. In contrast thereto, the other transport rollers arranged on the other tool shaft are supported in a freely rotatable manner. Herein it is irrelevant which of the tool shafts, the upper or the lower one, is driven with higher speed.

It has been shown that in the case of the known tool shafts and the circular knives mounted thereon an increase of the rotational speed by about 20 percent is enough to receive with certainty a leading, pulling longitudinal cut through the paper web.

According to another embodiment of the invention, such a pulling longitudinal cut can also be achieved by arranging a corresponding transmission between the one shaft to be rotated by any kind of drive and one of the two circular knives. It would also be possible to cause one of the two or both circular knives by means of separate drives to rotate at a higher speed as compared to the rotatively driven shaft(s).

While the above-mentioned embodiments are based on the fact that at least one of each two tool shafts carrying circular knives cooperating as cutters is driven at the same rotational speed at which the other shafts present in the folding unit are driven, in order to be able to connect at least one of the transport rollers abutting on the paper web from above and from below fixedly against rotation to this tool shaft and thus to guarantee a uniform transport of the paper web also in the area of the tool shafts, according to another embodiment of the invention, each two circular knives cooperating as cutters can be supported fixedly against rotation on their tool shafts. In contrast, the one or the two transport rollers abutting on the paper web from above and from below, respectively, are herein supported in a freely rotatable manner on the respective tool shafts. In this case, the transport rollers can be rotatively driven such that they transport the paper web conveyed between them at the desired web running speed towards the folding shafts or away from the folding shafts. Herein the tool shafts can be rotatively driven at a correspondingly higher speed so that the above-mentioned shearing cut of higher quality can be produced. Manufacturing a transport roller which is supported in a freely rotatable manner can be done using a simpler design and is thus economically more advantageous than a comparable design for a circular knife being supported in a freely rotatable manner. The transport rollers abutting on the paper web from above or from below, respectively, can be correspondingly driven by auxiliary shafts, for example. It would also be possible to drive only one of each two transport rollers correspondingly and to pull along the other transport roller quasi through their abutment on the paper web.

The cutting quality of the longitudinal cut(s) to be produced in a paper web in connection with a folding device can also be increased by bringing the cutting gap between the upper and lower knives to the amount of zero, if possible. As already mentioned above, in this respect it is known to push the circular knives axially together on the knife shafts. Due to manufacturing tolerances, however, a cutting gap of higher or lower width cannot be avoided. In accordance with the invention, a cutting gap of minimal width can be produced by pressing one of the opposing circular knives through a spring element against the mating knife. In a first exemplary embodiment, the circular knife attached fixedly against rotation on a shaft is loaded by means of a spring element in the axial direction such that its revolving rim always abuts in frictional engagement on the mating knife. As shown by the embodiments illustrated in the drawings, this spring element can preferably be an elastically deformable ring, such as, in particular, a rubber ring or else a steel spring or another spring element.

Further advantages and features of the invention can be gathered from the features further described in the claims as well as from the following exemplary embodiment.

SHORT DESCRIPTION OF THE DRAWINGS

The invention will be hereinafter described and explained in more detail by way of the exemplary embodiment illustrated in the accompanying drawings, in which

FIG. 1 is a view of two knife shafts, seen in the running direction of a paper web, according to a first embodiment of the invention, comprising a circular knife arranged fixedly against rotation on a first knife shaft and another circular knife arranged in a rotatable manner on a second knife shaft;

FIG. 2 is a schematic side view of a folding device comprising upstream knife shafts;

FIG. 3 a view of two knife shafts, seen in the running direction of a paper web, according to a second embodiment of the invention, comprising two circular knives, each of which is arranged in a freely rotatable manner;

FIG. 4 a view of two knife shafts, similar to FIG. 3, comprising two driven auxiliary shafts for driving two circular knives according to a third embodiment of the invention;

FIG. 5 a view of two knife shafts, seen in the running direction of a paper web, according to a fourth embodiment of the invention, comprising two circular knives arranged fixedly against rotation.

WAYS OF CARRYING OUT THE INVENTION

In accordance with FIG. 2, a buckle folding device 10 has a first upper folding pocket 12 and a second lower folding pocket 14. A first upper folding roller 16 and a second lower folding roller 18 are arranged upstream of the first folding pocket 12. A third upper folding roller 20 and a fourth lower folding roller 22 are arranged downstream of the second folding pocket 14. Such an arrangement of a buckle folding device 10 is known.

In accordance with FIG. 2, in the present exemplary embodiment, an upper cutting and transport roller 24 and a lower cutting and transport roller 26 are arranged upstream of the first and second folding rollers 16, 18. A paper web 28 is passed in the web running direction 30 through the two cutting and transport rollers 24, 26 and subsequently through the buckle folding device 10, wherein a first loop 32 is produced by the fact that the paper web 28 runs into the first folding pocket 12, and subsequently a second loop 34 is produced by the fact that the folded paper web 28 runs into the second folding pocket 14. The first loop 32 is folded by the second and third folding rollers 18, 20 to form a first fold, and subsequently the second loop 34 when passing between the third folding roller 20 and the fourth folding roller 22 is folded to form a second fold. This kind of longitudinal cutting of a paper web 28 and subsequent folding is per se known.

A lower transport roller unit 40 is mounted fixedly against rotation on the lower cutting and transport roller 26 shown in FIG. 1 by means of a screw 42. The outside of the transport roller unit 40 is provided with a rubber inlay 44. This lower transport roller unit 40 is associated with an upper transport roller unit 50. The outer ring 58 of this transport roller unit 50 is supported in a freely rotatable manner with respect to the upper shaft. For this purpose, a retainer jaw 52 of this transport roller unit 50 is supported fixedly against rotation on the upper shaft 24 by means of a screw 54. The retainer jaw 52 carries a ball bearing 56 arranged fixedly on the retainer jaw 52 through a blocking ring 57 in the axial direction 59, wherein the outer ring 58 is supported on the ball bearing 56, the outside of the outer ring 58 being provided with a rubber inlay 45. The paper web 28 runs between the two rubber inlays 44, 45 of the lower and upper transport roller unit 40, 50.

A lower retainer jaw 60 is supported fixedly against rotation in the axial direction laterally next to the lower transport roller unit 40 on the lower shaft 26. The retainer jaw 60 is surrounded by a ball bearing 64 carrying an outer retaining ring 66. Thus the retaining ring 66 is supported in a freely rotatable manner on the retainer jaw 60. The ball bearing 64 is arranged fixedly at the lower retainer jaw 60 by means of a blocking ring 61 in the axial direction 59. The lower circular knife 70 is held in the retaining ring 66 in a clamped manner between a recessed shoulder 67 of the retaining ring 66 and a distance piece held by a blocking ring 69 in the axial direction 59 against the retainer jaw 66. Due to the ball bearing 64 this lower circular knife 70 is, in the same way as the retaining ring 66, supported in a freely rotatable manner on the lower retainer jaw 60 and thus on the lower shaft 26.

The lower circular knife 70 cooperates with an upper circular knife 74. This upper circular knife 74 is supported fixedly against rotation on an upper retainer jaw 76 which is attached fixedly against rotation on an upper shaft 24 by means of a screw 78, wherein the upper circular knife 74 is loaded by an elastic ring 80 in the axial direction 59, i.e. in the longitudinal direction of the two longitudinal axes 82, 84 of the upper shaft 24 and the lower shaft 26.

Thus the elastic ring 80 presses in the axial direction 59 against the upper circular knife 74. By means of this pressure force the upper circular knife 74 is laid in the axial direction 59 laterally in a pressing manner against the lower circular knife 70, as shown in FIG. 1. The two circumferential rims of the two circular knives 70, 74 thus produce a shearing cut with a cutting gap, the size of which approaches zero.

In this way a clean longitudinal cut can be produced, and thus, for example, a lateral margin 83 can be separated with a clean quality cut from the remaining paper web 28. Each cutting rim of the two circular knives 70, 74 has a hollow grinding not shown in the figure. This enables to achieve a clean separation cut even if the circular knives 70, 74 have lost their exactly perpendicular alignment with respect to the axial direction by a small amount, for example, due to a small clearance in the ball bearing 64.

The elastic ring 80 (rubber ring) is held laterally framed by a press ring 81. The press ring 81 has an internal thread, and the upper retainer jaw 76 has an external thread, so that the press ring 81 can be screwed onto the retainer jaw, whereby the elastic ring 80 can be biased. The press ring is fixed in its adjusted position by means of a screw 85 which can radially screwed into the upper retainer jaw 76.

In order to produce this shearing cut as a leading pulling cut, a lower gear 90 having 24 teeth in the present case is attached fixedly against rotation on the lower shaft 26, which is actively driven in a rotatable manner. This lower gear 90 is in meshing engagement with an upper gear 92 having, for example, 20 teeth and being attached also fixedly against rotation on the upper shaft 24. The transmission consisting of these two gears 90 and 92 causes the upper shaft 24 to have a rotational speed which is higher by 20 percent than that of the lower shaft 26. This means that the upper circular knife 74 attached fixedly against rotation on the upper shaft 24 has a correspondingly increased rotational speed, which is transferred by this upper circular knife 74 onto this lower circular knife 70 by its frictionally engaging abutment on the lower circular knife 70. The lower circular knife 70 adopts this increased rotational speed, since it is supported in a freely rotatable manner through the ball bearing 64 on its lower shaft. In this way a sufficiently increased rotational speed of the circular knives 70, 74 as compared to the running speed of the paper web 28 can be guaranteed. In contrast thereto, the running speed of the web 28 is not increased. The running speed of the web 28 is based on the rotational speed of the lower transport roller unit 40 attached fixedly against rotation on the lower shaft 26. The rotational speed of the lower transport roller unit 40 is transferred through its rubber inlay 44 onto the upper transport roller unit 50 with the upper rubber inlay 45 being supported in a freely rotatable manner. The paper web 28 is thus transported through the two rubber inlays 44, 45 of the two transport roller units 40, 50 in the web running direction at a speed determined by the rotational speed of the lower shaft 26. The lower shaft 26 is now driven such that the speed of the paper web 28 corresponds to the speed which is also present when the paper web 28 runs through the downstream folding rollers 16, 18, 20, 22.

The embodiment shown in FIG. 3 of an upper and a lower cutting and transport shaft 24, 26, between which the paper web 28 passed through is separated with a longitudinal cut, differs from the embodiment shown in FIG. 1 in so far as not the two shafts 24, 26 are given different rotational speeds by means of a transmission, but that by means of a transmission the one, in this exemplary embodiment, the lower shaft 26 is connected directly to the—in this exemplary embodiment—upper circular knife 74.

A lower transport roller unit 40 is supported fixedly against rotation by means of a screw 42 on the lower cutting and transport shaft 26 in the same way as in the case of the embodiment according to FIG. 1.

In the case of the embodiment according to FIG. 3, the lower circular knife 70 is also held by clamping in an outer retaining ring 66 in the same way as in the case of the embodiment according to FIG. 1, wherein the outer retaining ring 66 is in turn supported through a ball bearing 64 in a rotatable manner on a lower retainer jaw 60 which is arranged fixedly against rotation on the shaft 26 by means of the screw 62. The support for the lower circular knife 70 is identical for the embodiments according to FIGS. 1 and 3.

An upper transport roller unit 50.3 is arranged fixedly against rotation on the upper cutting and transport shaft 24. This upper transport roller unit 50.3 corresponds to the lower transport roller unit 40. It is attached fixedly against rotation on the upper shaft 24 by means of a screw 54. The paper web is passed between the transport roller units 40, 50.3. Herein the rubber inserts 44, 45 of the two units 40, 50.3 abut in a pressing manner with frictional engagement from below and from above, respectively, on the paper web 28.

The upper circular knife 74 is supported fixedly against rotation in an outer retaining ring 94. The outer retaining ring 94, in turn, is attached in a rotatable manner through a double-track ball bearing 96 at an upper retainer jaw 98. The upper retainer jaw 98, in turn, is attached through a screw 100 at the upper shaft 24. The double-track ball bearing 96 is held by means of a locking ring 102 in an undisplaceable manner at the upper retainer jaw 98 and thus at the shaft 24.

The upper circular knife 74 is held in a pressed manner in the axial direction 59 between a stepped in shoulder 104 of the outer retaining ring 94 and a press ring 81 screwed onto this retaining ring 94 and secured by means of a screw 108. Herein an elastic ring 80 is arranged between the upper circular knife 74 and the shoulder 104. This elastic ring 80 (rubber ring) presses in the axial direction 59 laterally against the upper circular knife 74. Thereby the upper circular knife 74 is pressed laterally against the lower circular knife 70 and thus a frictionally engaging abutment between the two circular knives 70, 74 is achieved in the same way as it is the case in FIG. 1.

The outer retaining ring 94 which is rotatable about the upper shaft 24 has at its—in FIG. 3—left end region a sprocket 112 having 20 teeth in the present exemplary embodiment. This sprocket 112 cooperates with a gear 90 attached fixedly against rotation on the lower shaft 26. In this exemplary embodiment the lower gear has 24 teeth. The lower shaft 26, which has been made to rotate by any kind of drive, transfers its rotation to the lower gear 90. The lower gear 90 which is in meshing engagement with the upper sprocket 112 causes the sprocket 112 to rotate faster by—in this exemplary embodiment—20 percent than the lower shaft 26. This results in a rotational effect which is different from the embodiment according to FIG. 1. The rotation of the sprocket 112 acts on the upper circular knife 74. This also causes the upper circular knife 74 to rotate at a rotational speed which is higher by 20 percent than that of the lower shaft 26.

The rotational speed of the upper circular knife 74 is transferred to the lower circular knife 70 by the frictionally engaging abutment of the two circular knives 70, 74, as it has already been described above in connection with FIG. 1. In this way, in the paper web 28 a so-called leading pulling longitudinal cut through the paper web 28 can be produced.

In this embodiment the upper shaft 24 is dragged along through the two transport roller units 40, 50.3; a separate rotational drive for the upper shaft 24 is dispensable. It would be possible to form the upper transport roller unit 50.3, in the same way as in the case of the embodiment according to FIG. 1, like the transport roller unit 50 and thus freely rotatable relatively to the upper shaft 24. In this case the upper shaft 24 could remain at rest, without rotation.

The upper circular knife could also be made to rotate faster as compared to the lower shaft 26 by means of any other drive instead of by means of the lower gear 90.

In the embodiment illustrated in FIG. 4, upper and lower transport roller units which are fixed against rotation are arranged on the two shafts 24, 26, wherein an upper transport roller unit 50.3 and a lower transport roller unit 40 are shown in the drawing. The paper web 28 passes between the two transport roller units 40, 50.3, which correspond to the respective transport roller units of FIG. 3, wherein rubber inlays 44, 45 which are provided in each of the transport roller units abut thereon from below and from above in a pressing and frictionally engaging manner.

An upper circular knife 74 is supported in a freely rotatable manner about the upper shaft 24 in the axial direction 59 next to the upper transport roller unit 50.3. The upper circular knife 74 is supported in a freely rotatable manner through a ball bearing 64 on an upper retainer jaw 60.4, which is arranged fixedly against rotation on the upper shaft 24. The retainer jaw 60.4 with its mount of the upper circular knife 74 corresponds to the lower retainer jaw 60 arranged fixedly against rotation on the lower shaft 26 in FIG. 1. The upper retainer jaw 60.4 provided in the upper shaft 24 in FIG. 4 differs from the retainer jaw 60 illustrated in FIG. 1 in so far as a sprocket 114 is attached fixedly against rotation at the radial circumference of the outer retaining ring 66 of the upper retainer jaw 60.4. This sprocket 114 cooperates with a sprocket 116 provided on a gear 118. This gear 118 is attached fixedly against rotation on an upper auxiliary shaft 120. The outer retaining ring 66 of the upper retainer jaw 60.4 can be made to rotate in any way through the gear 118 and its sprocket 116 by means of a rotational drive (not shown in the drawing) for the auxiliary shaft 120. In correspondence with the above-mentioned embodiments, its rotational speed can then, for example, be selected to be higher by 20 percent than the rotational speed of the two transport roller units 50.3, 40 of the two shafts 24, 26.

The lower retainer jaw 60.5 provided on the lower shaft 26 corresponds to the upper retainer jaw 60.4 with the difference that instead of the distance piece 68 of the upper retainer jaw 60.4 a distance piece 68.4 is provided, which in the present exemplary embodiment has an angular shape and is supported in the axial direction through a (still present) locking ring 69 on the outer retaining ring 66. There is an elastic ring 80 provided between the L-shaped distance piece 68.4 and the lower circular knife 70. The lower circular knife 70 is pressed through the elastic ring 80 against the stepped in shoulder 67 of the outer retaining ring 66. In this way, the lower circular knife 70 is laid with frictional engagement against the upper circular knife 74 in the axial direction 59. Otherwise the lower retainer jaw 60.5 corresponds to the upper retainer jaw 60.4 in so far as a sprocket 114 is also attached fixedly in the outer retaining ring 66. The sprocket 114 is in meshing engagement with a sprocket 116 of another gear 118 attached fixedly against rotation on a lower auxiliary request 122.

In the present exemplary embodiment the rotational speeds of the two auxiliary shafts 120, 122 are equally high. Since the transmission ratios of the gears 118 to the lower retainer jaw 60 and the upper retainer jaw 60.4, respectively, are identical, the two circular knives 70, 74 also rotate with exactly the same rotational speed. This rotational speed is—as already mentioned above—higher by about 20 percent than the rotational speed of the two shafts 24, 26. In this way a leading pulling longitudinal cut can be produced in the paper web 28 using the two circular knives 70, 74.

The embodiment according to FIG. 4 can also be used to carry out a longitudinal cut in a middle portion of the paper web 28, since the upper and the lower retainer jaw 60.4, 60.5 have a finite distance 130 and 132, respectively, from the paper web 28. In the case of the embodiment according to FIG. 3 this would be possible only if the clearance present in the axial direction 59 between the lower gear 90 and the paper web 28 was large enough.

In the embodiment according to FIG. 5 the upper circular knive 74 is supported fixedly against rotation on the upper cutting and transport shaft 24, as it is the case in FIG. 1. Herein the upper circular knive 74 is pressed against the—in FIG. 5 towards the left—outer left shoulder 86 of the upper retainer jaw 76 by means of an interposed elastic ring 80 by a press ring 81, which is screwed onto the upper retainer jaw 76 attached fixedly against rotation on the shaft 24 by means of a screw 78. The press ring 81, in turn, is held in its screwed-on position by means of a screw 85 screwed radially into the upper retainer jaw 76.

The lower circular knife 70 is also attached fixedly against rotation on the lower cutting and transport shaft 26. Thus a lower retainer jaw 60.6 is attached fixedly against rotation on the shaft 26 by means of a screw 62. A press ring 81.5 is screwed in the axial direction onto this lower retainer jaw 60.6, wherein the press ring 81.5 is retained in its screwed-on position by means of a screw 85 in its position at the retainer jaw 60.6. The press ring 81.5 in the axial direction presses the lower circular knife 70 directly against a—in FIG. 5 right—outer shoulder 87 of the lower retainer jaw 60.6. The lower circular knife 70 is held in an undisplaceable manner between the press ring 81.5 and the shoulder 87 of the retainer jaw 60.6

The two cutting and transport shafts 24, 26 are driven such that the paper web 28 can be separated in the web running direction—using a longitudinal cut—by the two circular knives 70, 74, as it has already been mentioned above.

A lower transport roller unit 40.5 is supported in a freely rotatable manner on the lower cutting and transport shaft 26. For this, its lower retainer jaw 51 is arranged fixedly against rotation on this lower shaft 26 by means of a screw 42. An outer retaining ring 66.5 is supported in a rotatable manner through a ball bearing 144 on the lower retainer jaw 51. The rubber inlay 44 is attached at the outer retaining ring 66.5, as it is the case with the above-mentioned lower transport roller unit 40. Thus, the outer retaining ring 66.5 can be rotated relatively to the lower cutting and transport shaft 26.

A sprocket 146 radially protruding from the outer retaining ring 66.5 is provided for rotating the outer retaining ring 66.5. This sprocket is in meshing engagement with a gear 148 attached fixedly against rotation on the auxiliary shaft 122, which is supported at a constant distance to the lower shaft 26. Thus, the outer retaining ring 66.5 with its rubber inlay 44 can be rotatively driven at any desired speed by driving the auxiliary shaft 122 by means of the gear 148 and the sprocket 146.

A comparable freely rotatable support is also provided for the upper transport roller unit 50.5. Herein an outer retaining ring 156 is held through a retainer jaw 52.5 supported fixedly against rotation on the upper shaft 24 by means of a screw 54 through a ball bearing 56 supported on the retainer jaw 52.5. A sprocket 148 is formed at the outer retaining ring 156 in a way comparable to the outer retaining ring 66.5 of the lower transport roller unit 40.5, wherein the sprocket 148 cooperates with a gear 150. The gear 150 is attached fixedly against rotation on an auxiliary shaft 120. A rubber inlay 45 is attached at the outer retaining ring 156, as it is also the case in a comparable way with the upper transport roller unit 50 (FIG. 1).

Through the auxiliary shaft 120 the outer retaining ring 156 and thus the upper rubber inlay 45 can be given rotational speed, and the same is true for the lower rubber inlay 44 through the auxiliary shaft 122. These rotational speeds are high enough for transporting the paper web 28 held with frictional engagement between the two rubber inlays 44, 45 at the desired web running speed through the area of the cutting and transport rollers 24, 26. This web speed is equally high in the area of the cutting and transport shafts 24, 26 and the folding rollers (FIG. 2).

In contrast thereto, the two circular knives 70, 74 can be driven, in the present exemplary embodiment, at rotational speed which is higher by about 20% (percent), so that the desired shearing cut of high quality can be produced in the paper web 28, as it has been mentioned above. The rotational speed of the two circular knives 70, 74 which is higher as compared to that of the transport shafts is achieved by corresponding rotational drives for the two cutting and transport rollers 24, 26, on which the respective two circular knives 70, 74 are arranged fixedly against rotation.

Claims

1-17. (canceled)

18. A device for folding a paper web comprising

lower and upper tool shafts arranged upstream or downstream of folding rollers, said lower tool shaft carrying at least one lower circular knife, and said upper tool shaft carrying at least one upper circular knife, wherein said lower and upper circular knives are arranged and can be rotatively driven for cutting such that at least a longitudinal cut can be produced in a running direction of said paper web in said paper web running through said upper and lower tool shafts, and

transport roller units for transporting said paper web through and between said upper and lower tool shafts and towards said folding rollers and/or away from said folding rollers and towards said upper and lower tool shafts and through and between them,

wherein

said circular knives are rotatively driven such that speed components of said circular knives in said web running direction are higher than said web running speed of said paper web,

rotational drives for at least one of said upper and lower tool shaft and for at least one of said folding rollers folding roller are such that web running speeds of said paper web through between said upper and lower tool shafts and through between said folding rollers are equally high,

at least one upper circular knife is supported in a freely rotatable manner on said upper tool shaft,

at least one lower circular knife cooperating with said at least one upper circular knife for cutting is supported in a freely rotatable manner on said lower tool shaft, and

the upper and lower circular knives are rotatively driven at a higher speed with respect to said tool shafts, so that each circular knife has a higher rotational speed as compared to that of said tool shafts on which it is placed.

19. The device according to claim 18, wherein a transmission is provided between at least one rotatively driven tool shaft and at least one circular of said circular knives.

20. The device according to claim 18 wherein a transmission between at least one of said circular knives and a rotatively driven auxiliary shaft is provided.

21. The device according to claim 18, wherein circular knives cooperating for cutting are pressed together in an axial direction.

22. The device according to claim 18, wherein

at least one transport roller unit is arranged fixedly against rotation on one of said tool shafts, and

at least one transport roller unit is supported in a freely rotatable manner or in a fixed manner on another of said tool shafts.

23. The device according to claim 21, wherein an elastic element presses in said axial direction against one of said circular knives such that said one of said circular knives abuts with frictional engagement against another of said circular knives cooperating with said one of said circular knives for cutting.

24. The device according to claim 23, wherein said elastic element is an elastically deformable ring, such as, in particular, a rubber ring or a steel spring.

25. The device according to claim 18, wherein a cutting rim of at least one of said circular knives has a hollow grinding.

26. The device according to claim 18, wherein rotational speeds of the circular knives are about 20% higher than said web running speed of said paper web.