DE4236347A1 - Longitudinal cutter for plastics sheeting - has blade heads on carrier plates with motor, drive nut, and spindle - Google Patents

Abstract

The cutter has upper and lower blade heads. Each blade head is located on a carrier plate (3), which is guided on blade head bars (2). A fixed threaded spindle (4,5) passes at a distance through upper and lower carrier plates. Each plate carries a motor (8,9), and a drive nut (7), which meshes with the spindle and is in drive connection with the motor. A motor-driven spline shaft (14) passes loosely through the lower carrier plates. The lower blades (13) of the lower blade heads are in drive connection with the shaft. The upper blade heads (10) support circular blade carriers, with pneumatic setting drives. USE/ADVANTAGE - For length of sheeting, esp. plastic. Blade heads can be moved separately or in pairs, for independently adjustable cutting widths. Cuts cleanly independently of sheeting thickness and type.

Description

The invention relates to a longitudinal cutting device for Foil webs, in particular plastic film webs with a A plurality of upper ones guided on at least one upper rod Cutter heads and a plurality of at least one lower Rod guided, together with the upper cutter heads in pairs menworking, lower cutter heads and separate drives for each cutter head for the purpose of moving to its management post The invention also relates to a method for running in the upper knife of a pair of knife heads in the cutting position in this longitudinal cutting device, and a method for Adjustment of the zero point of a pair of cutter heads on this longitudinal cutting device.

The invention has for its object a slitting device for film webs, in particular plastic films travels with a plurality of in the direction of the web width create pairs of knife heads where the knife heads move individually or in pairs in the direction of the web width can, so that the cutting widths are independent of can be adjusted to each other. Furthermore, a slitting device for plastic sheeting to be created regardless of the film thickness and the film material clean Cut marks delivers. In addition, a procedure for retracting should the upper knife is created in the cutting position in which no disturbances in the gating process and no threading enter. In addition, a simple method for Zero point adjustment of a pair of cutter heads are created,  all the more so on all pairs of cutter heads regardless of the degree of wear the knife, especially the upper knife, has the same cutting conditions conditions, in particular the same contact pressure of the upper knife to reach. Further advantages result from the following Description.

This task is at the slitting mentioned above device according to the invention solved in that each cutter head is attached to a carrier plate guided on the rods, the carrier plates of the upper and lower cutter heads at a distance pierced by an upper or lower fixed threaded spindle are attached to each support plate and a motor with the Threaded spindle in engagement with the motor drive moderately connected drive nut is rotatably mounted and the lower carrier plates by a motor-driven spline are loosely pierced to which the lower knives of the lower Cutter heads are connected to the drive. All cutter heads are equipped with their own traction motor, so that they are individually or who move in pairs in the transverse direction of the film web that can. The travel path and thus the cutting width can be changed can be preprogrammed numerically. Since all the support plates of the above Drive the knife heads on the same fixed threaded spindle there is also a compact dimensioning of the carrier plates with a larger number of cutting edges. The same applies to the carriers plates of the lower cutter heads. Through the individual process availability of the upper cutter heads, it is also possible to vidual zero point adjustment of the cutter heads so that all pairs of cutter heads regardless of their state of wear or unavoidable tolerances work with the same starting pressure can.

According to the preferred embodiment of the invention The upper cutter heads carry circular knife holders that with pneumatic adjustment acting in the Z-axis and X-axis drives are equipped. These adjustment drives allow one  trouble-free delivery of the upper knife to the driven Lower knife. In particular, the upper knife can initially be in Rich direction of the Z axis can be lowered to a position in which the film web is cut, and then the top knife with a continuous cut to the running lower knife be put.

According to the preferred embodiment of the invention The knife holders of the upper cutter heads are equipped with a switch that can be actuated by rotating the upper knife the associated motor. With the help of this switch can an exact separate zero point adjustment for each cutter head be made, which will be discussed in more detail below.

Furthermore, it is preferably provided that the rotational position the circular knife holder is adjustable in the Z axis. The settings Availability is limited to a few degrees, preferably 1 to 4 °. Due to the attainable inclination of the plane of the upper knife The direction of the film web results in the overlap area of the Upper and lower knives a clearance angle that extends to the rear, d. H. opens in the direction of the cut web. The clearance angle is beneficial for a clean cut and avoiding the Thread or lint formation.

In a further embodiment of the invention, it is provided hen that one of the cutter head pairs as a double cutter head pair is formed and the two knife levels of the upper double knife head are divergent aligned in the direction of travel of the film web. Due to the divergent alignment of the circular knives of the upper dop pel knife head are also in the overlap area with the corresponding lower knives clearance angle created, which in open in the direction of travel of the film web. Through this clearance angle the same cut improvement results as in the above ge named rotational position of the individual upper knives. Here are the two knives of the double knife head expediently on one  Axis mounted, which run in the direction of the film web is bow. Due to this slight deflection of the bearing axis in a simple way the weakly divergent alignment of the two Knife and thus the formation of the desired clearance angle between between the upper knives and the associated lower knives other parallel, reached.

The lower cutter heads are preferably with knives, ins special pot knives equipped, the cutting angle β at the Cutting edge is less than 90 °. The angle is preferably β 85 to 89.5 °, in particular 87 to 89 °. Through this training the lower knife also improves the cut quality. The scope of processable film materials is expanded. In addition, the service life of the pair of knives is extended if the Angle β is less than 90 °.

It is also provided that the ends of the rods and Threaded spindles are firmly attached to two parallel cheeks and the Ge formed from the cheeks, rods, and lead screws position the knife heads against a stationary base is movable in the X direction. Since at the cut edges of the ge the strips of film formed a slight thickening due to the cut or bulging occurs when the cut is wound up stripes a bulge at the edges. To do this avoid the device according to the invention compared to stationary frame, the z. B. be an upstream machine can, as well as in relation to the rolls for winding up the strips fen in the direction of the X axis, d. H. the width of the film web marginally, especially in the order of magnitude Slowly back and forth 1 cm, causing the thickened Spread out the edges of the strips and the bulge of the rolls is reduced. For this purpose, it is advisable between the cheeks two bars attached, four on a stationary base Bearing blocks mounted, in which the rods are slidably mounted and is also a motor on the stationary frame, in particular a geared stepper motor attached to which a shaft drives  is moderately connected, the thread end with a threaded hole the adjacent cheek is engaged. The shaft rotation of the Motors can be attached to the shaft by means of belts or the like sensitive disc can be transferred.

In a further embodiment of the invention are on the carrier plates of the upper cutter heads means for mounting the blade neck tern provided so that the carrier plates additionally with blades holders can be equipped. While the circular knife holder generally on the film web start side of the carrier plates are arranged, are the mounting means for the blade holder attached to the film drain side. Expediently the carrier plates are then fitted with blade holders that pass through an actuator between an interface and an outside are pivotable. With the circular knife raised The film can then be held by the in the cutting position swiveled blade holder can be cut lengthways.

The above-mentioned procedure for retracting the upper knife a pair of cutter heads in the cutting position in which it is together cut the film with the lower knife of the pair of knife heads det, is in the above-mentioned slitter characterized in that the disengaged upper knife at a distance in the X direction from the cutting edge of the lower part sers in the direction of the Z axis in the film web while doing so the film web separates, then the upper knife in the direction the Z-axis back to that for its employment on the lower knife required height position and then in the direction of X-axis until reaching the cutting position on the lower knife and the desired starting pressure. This way, un depending on the material and the thickness of the film to be cut a trouble-free cut, especially a trouble-free cut beginning can be reached. It is essential that the Obermes water at a sufficient distance from the lower knife, the example may be 2 to 4 mm, d. H. without direct help from the sub  knife completely cuts the film web. This is depending a more or less deep depending on the film material and thickness Immerse the upper knife in the direction of the Z axis in the foils track required. Depending on the film material and thickness considerable forces are required, which weigh up to 100 kg and more can. Only when this cut is made is the waiter knife in the position to the lower knife, and in a two-stage movement, in which the waiter first knife raised in the direction of the Z axis to the cutting height and only laterally, d. H. in the direction of the X axis the lower knife is turned on. This kinematics becomes a trouble-free cut of the film web reached. Preferably the movements of the upper knife are pneumatically controlled ert.

The procedure for adjusting the zero point of a cutter head This is a couple in the above-mentioned slitter characterized in that the disengaged upper knife at a distance from the cutting edge of the running lower knife in Descends in the direction of the Z axis to the cutting height and then moto risch in the direction of the X-axis up to the touch and take traversed by the lower knife, whereby the traction motor of the upper Cutter head is switched off. This way you can be independent on the strength, wear or tolerance of the top and / or lower knife a reproducible zero point setting be enough. After this adjustment of the zero point the desired setting pressure of the upper knife is set numerically by moving the upper knife holder by one by its traction motor the line pressure corresponding distance, z. B. 0.2 mm, further against the lower knife is driven. The zero points according to the invention position allows for very different wear conditions of the cutter head pairs an equivalent zero point adjustment on all Pairs of cutter heads and the Beauf starting from this zero point hitting all pairs of cutter heads with the same contact pressure, see above that the same cutting conditions are achieved. This  Zero adjustment can be done individually for all cutter head pairs Appropriate programming is achieved on the control panel of the facility become. The pairs of knife heads adjusted in this way can be determined by numeri input of the desired contact pressure is automatically applied become. An adjustment of the contact pressure by spring tension by hand is no longer necessary.

The invention will now be described with reference to the drawing described. Show it

Figure 1 is a front view of a longitudinal cutting device according to the invention in a schematic representation.

Fig. 2 is a section along the line II-II of Fig. 1;

Fig. 3 is a section along the line III-III of Figure 2 on an enlarged scale.

. Figure 4 shows a cutter head pair of the device according to Fig 1 in an enlarged scale, partly in section and partly in view.

Fig. 5 is a section along the line VV of Fig. 4;

Fig. 6 is a section along the line VI-VI of Fig. 5;

Figure 7 is an upper double rod-cutter head on an enlarged dimension, partly in section.

Fig. 8 is a partial view of the traversing part for transverse travel availability of the device according to the invention;

Fig. 9 is a section along the line IX-IX of Fig. 8;

FIG. 10 is a side view of a blade holder to a support plate;

Fig. 11 is an axial section of the clinical holder shown in Fig. 10;

Figure 12 shows the radial section of a preferred embodiment of the lower knife.

Figure 13 is a schematic representation of the motion sequence of the upper blade when moving into the cutting position. and

Fig. 14 is a schematic representation of the sequence of movements of the upper knife in the zero point adjustment.

According to FIGS. 1 and 2, the longitudinal cutting device according to the invention comprises between two cheeks 1, four guide bars 2 of which are shown in Fig. 1 just 3. On the two obe ren guide rods 2 five carrier plates 3 are guided displaceably in the transverse direction. These plates are not visible in Fig. 1 bar. In the same way, two support plates 3 are slidably guided on the lower guide rods 2 . Between the cheeks 1 in the area of the upper support plates 3, a fixed threaded spindle 4 and in the area of the lower support plates 3, a fixed threaded spindle 5 . The threaded spindles 4 and 5 are with threaded nuts 6 and 7 in engagement, which are mounted on the carrier plates 3 rotating bar, as will be explained below with reference to FIG. 3. An upper cutter head 10 with a non-driven upper cutter 11 is attached to the upper carrier plates 3 . A lower cutter head 12 with a lower cutter 13 is rotatably mounted on the lower support plate 3 . In the lower part of the device, a spline shaft 14 is also provided, which loosely pierces the lower carrier plates 3 and is connected to a rotary drive motor (not shown) on the outside of a cheek 1 . The V-shaft 14 is drive-wise connected to the V-belt pulleys 16 of the lower cutter heads 12 via V-belts 15 .

The cheeks 1 are connected in their lower region by two Stan conditions 17 , which are guided displaceably in bearing blocks 18 , which in turn are fixedly mounted on a stationary base 19 . The displacement amplitude of the device 1 - 17 In the La gerböcken 18 is of the order of 1 cm. For further explanation of this traversing device, reference is made to the explanation of FIGS. 8 and 9 below.

Fig. 3 shows the implementation of the threaded spindle 4 and the guide rod 2 through the support plate 3 in section. To guide the guide rod 2 , a receptacle bushing 101 is inserted into the plate 3 , which holds a ball bushing 102 by means of retaining rings, in which the guide rod 2 runs. In the carrier plate 3 , a receptacle 103 is also used, which holds a deep groove ball bearing 104 by means of retaining rings. In the Ril ball bearing 104 , a tubular shaft 105 is mounted concentrically to the Ge threaded spindle 104 . The tubular shaft 105 carries, on the one hand, the threaded ball bushing 6 located in the engagement of the threaded spindle 4 and, on the other hand, a toothed belt pulley 107 attached by means of a key 106 . The toothed belt pulley 107 is driven by the motor 8 (see FIG. 2) via toothed belts.

In the pair of cutter heads shown in FIG. 4, the upper cutter head is shown in the view and the lower cutter head with its drive in section. A toothed belt pulley 20 is seated on the drive spline shaft 14 and is mounted in a bearing bush 21 embedded in the carrier plate 3 . In the carrier plate 3 , a bearing bush 22 is also embedded, in which the shaft 23 of the toothed belt pulley 15, which is driven by toothed belt 15, is supported by ball bearings 16 . On the shaft 23 , the pot knife 13 is clamped by means of pressure cover 24 and screw 25, which cooperates with the upper knife 11 .

The receptacle 26 for the storage of the upper knife 11 carries an electrical contact switch 27 , 27 a for the circuit of the associated traction motor 8 . The switch 27, 27a operates so that the motor circuit is closed only in a certain rotational position of the blade holder 28 so that when the stationary circular blade 11 is moved up from the side of the rotary pot diameter 13, at the moment of contact of the blade 11 and 13 the knife 11 is carried along by the knife 13 and the switch 27 , 27 a is opened so that the motor 8 is stopped. The meaning of the switch 27 , 27 a for the zero point adjustment is explained in more detail below.

The upper cutter head shown in Fig. 5 has a pneumatic cylinder 29 for receiving the pneumatic actuating piston 26 , a cylinder cover 30 for upper guidance and in the annular space between the cylinder 29 and piston 26, a compression spring 31 which the piston 26 in the absence of pneumatic actuation hits in the top position. The piston 26 carries a receptacle 34 for a pneumatic lifting cylinder at the bottom. In the Zy cylinder, a piston 35 is displaceable in the transverse direction. The piston 35 is held in the illustrated left stop position by a compression spring 36 which is supported on the cylinder cover 37 . When the piston 35 is acted upon pneumatically, the piston 35 is displaced towards the cover 37 against the force of the spring 36 , the right stop position of the piston 35 being adjustable by the threaded pin 38 . Reference numeral 48 denotes an O-ring of the piston 35 . On the rod 40 of the piston 35 , a pair of sockets 43 , 44 with an inclined ball bearing 45 is attached by means of screw 41 and cover 42 . On the outer socket 44 , the Kreismes water 11 is mounted and hold ge by means of plate spring 46 and pressure nut 59 . It can be seen that the freely rotatable upper knife 11 by the pneumatic piston / cylinder unit 26/29 in the direction of the Z-axis and by the pneumatic piston / cylinder unit 34 , 35 in the direction of the X-axis is pneumatically displaceable, the pneumatic without the Knife 11 is held in the raised position and the position reset by the lower knife 13 .

The sectional view of FIG. 6 shows that the piston 26 is guided by a key 49 in the socket 33 without rotation. In the mounting flange 32 for the socket 33 , a threaded bore 51 is formed with a recess 51 a. The socket 33 has a nose 50 which projects into the recess 51 a. The nose 50 is acted upon on the one hand by a spring pin 53 and on the other hand by the grub screw 52 . It can be seen that the screw 52, the rotational position of the piston 26 and thus the knife 11 varies within narrow limits and thus a Freiwin angle between the upper knife 11 and the lower knife 13 can be created.

Fig. 7 shows a double knife head, the pneumatic piston / cylinder unit 26/31 corresponds to that of FIG. 5 in wesent union. On a weakly (not recognizable) bent pipe axis 60 socket pairs 43 , 44 are again provided with ball bearings 45 arranged between them. On the outer socket 44 sits a circular knife 11 , which is held by means of a plate spring (not shown) and pressure nut 59 . To the pipe shaft 60, a pneumatic cylinder is at both ends 61 is attached with a lid 62 in which a piston projecting into the tube axis 60 of the piston rod 63 is slidable a 63rd The two pistons 63 , of which the right one is not shown, are acted upon by a common compression spring 64 . A cross pin 65 in the piston rod 63 a extends through the slotted tube axis 60 and grips into the inner sleeve 43 , so that the package 43 - 45 with the knife 11 is moved according to the movement of the piston 63 , 63 a under pneumatic action or the spring force .

FIGS. 8 and 9 a gear stepper motor 70 is mounted by means of bracket 71 to the bearing block 18. By the motor 70 , a traversing shaft 75 is driven via a toothed belt pulley 72 by means of toothed belt 73 and toothed belt pulley 74 , which is supported in a bushing 76 with angular contact ball bearing 77 . The shaft 75 has a threaded stub 75 a, which is in engagement with a traversing nut 78 , which is inserted into the cheek 1 . It can be seen that during operation of the stepper motor 70, the cheek 1 and thus the entire device can perform a slow reciprocating movement of low amplitudes relative to the stationary underframe on which the console 19 is fastened.

According to FIGS. 10 and 11, the upper support plate 3 in the rear region a fork-shaped bearing 80 and a La gerbock 81st A worm gear 84 is pivoted on the bearing block 81 by means of bolts 83 . On the gear block 84 , the mounting disk 82 is laterally mounted for a total of eight clin 85 . The disk 82 can be rotated by means of the feed wheel 86 if the blade 85 in the cutting position is to be replaced. The blades 85 can be fastened by means of knurled screw 87 . The fastening disk 82 with the blades 85 is surrounded by a protective box 88 , from which only the blade 85, which cuts into the film web 89, projects below. On the worm gear 84 , a bracket 90 is also introduced, which is pivotally connected to a fork head 91 . Zvi rule the joints 80 and 90/91 arranged a double-acting pneu matic cylinder 92, with which the blade wheel pivoted down 82 into the position shown in Fig. 10 cutting position to the film web 89 and from the cutting position pivoted who can the.

Fig. 12 shows the radial section of the cup knife 13 , from which it can be seen that the angle β at the cutting edge 13 a is less than 90 °. Generally the angle is between 85 and 89.5 °. In Fig. 12, β is exaggerated for clarity. The knife surface 13 ^b has a concave shape in cross section (round cut).

Fig. 13 shows schematically the movement sequence of the upper circular blade 11 in the position at the lower knife 13. The upper knife first moves from position A, in which it is at a distance from the cutting edge of the lower knife located in C in both the direction of the Z axis and the X axis, in the direction of the Z axis down to a position B, in which separates the film web from the upper knife without direct help from the lower knife. If the web is cut in this way, the upper knife is moved in the direction of the Z axis to position B ', which is at the height of the position on the lower knife. In a third step, the upper knife is then moved in the direction of the X axis into position C, in which the pair of cutters cooperates in a cutting function. This kinematics of the upper knife avoids difficulties when cutting into the film web.

Fig. 14, finally, shows the movement sequence of the upper blade at the zero point adjustment. From a position A, in which the upper knife has a distance from the cutting edge of the lower knife both in the direction of the Z axis and in the direction of the X axis, the upper knife is moved in the direction of the Z axis into a position B in which it is at the height of attack in relation to the lower knife. Then the upper knife is moved to the running lower knife by moving in the direction of the X axis. In position C, the two knives come into contact, as a result of which the associated traction motor is switched off by means of switches 27 , 27 a. Position C represents the zero point from which the starting pressure can be specified.

Reference list

1 cheeks
2 guide rods
3 carrier plates
4 threaded lockers
5 threaded spindle
6 threaded nut
7 threaded nut
8 engine
9 engine
10 upper cutter head
11 top knives
12 lower cutter head
13 lower knives
13 a cutting edge of the lower knife
13 ^b concave knife surface
14 spline shaft
15 V-belts
16 V-belt pulley
17 sticks
18 bearing blocks
19 base
20 toothed belt pulley
21 bearing bush
22 bearing bush
23 wave
24 pressure cover
25 screw
26 receiving pistons
27, 27 a contact switch
28 knife holder
29 cylinders
30 cylinder covers
31 compression spring
32 mounting flange
33 socket
34 receiving cylinders
35 pistons
36 compression spring
37 cover
38 grub screw
39 -
40 piston rod
41 screw
42 cover
43 socket
44 socket
45 angular contact ball bearings
46 disc spring
47 -
48 O-ring
49 key
50 nose
51 threaded hole
51 a recess
52 grub screw
53 spring pin
54-58 -
59 pressure nut
60 tube axis, slightly curved
61 pneum. cylinder
62 cover
63 pistons
63 a piston rod
64 compression spring
65 cross bolts
66-69 -
70 stepper motor
71 bracket
72 toothed belt pulley
73 timing belts
74 Timing belt pulley
75 traversing shaft
75 a thread stub of the traversing shaft
76 socket
77 angular contact ball bearings
78 traversing nut
79 -
80 fork-shaped bearings
81 bearing block
82 mounting washer
83 bolts
84 worm gears
85 blades
86 delivery wheel
87 Knurled screw
88 protection box
89 foil web
90 support bracket
91 clevis
92 pneumatic cylinders
93-100
101 receptacle
102 ball bushing
103 receptacle
104 deep groove ball bearings
105 tubular shaft
106 key
107 timing belt pulley

Claims (14)

1.Longitudinal cutting device for film webs with a greater number of upper cutter heads guided on at least one upper rod and a plurality of lower cutter heads guided on at least one lower rod, which work in pairs with the upper cutter heads, and separate drives for each cutter head for their travel on the Guide rods, characterized in that
each cutter head is attached to a carrier plate ( 3 ) guided on the rods ( 2 ),
the carrier plates ( 3 ) of the upper and lower cutter heads are pierced at a distance from an upper or lower fixed threaded spindle ( 4 or 5 ),
a motor ( 8 or 9 ) is attached to each carrier plate ( 3 ) and a drive nut ( 6 or 7 ), which is in engagement with the threaded spindle ( 4 or 5 ) and is connected to the motor ( 8 or 9 ) by drive. is rotatably mounted, and
the lower support plates ( 3 ) are loosely pierced by a motor-driven spline shaft ( 14 ), to which the lower knives ( 13 ) of the lower cutter heads are connected by drive. 2. Device according to claim 1, characterized in that the upper cutter heads ( 10 ) carry circular knife holders ( 34 - 47 ) which drive with pneumatic adjustment working in the Z-axis and X-axis ( 26 , 29 or 34 , 35 ) are equipped. 3. Device according to claim 2, characterized in that the knife holder (41-47) of the upper cutter heads are provided with an operable upon rotation of the blade (11) switch (27, 27 a) for the associated motor (8). 4. Device according to claim 2 or 3, characterized in that the rotational position of the circular knife holder ( 41 - 47 ) is adjustable in the Z-axis. 5. Device according to one of claims 1 to 4, characterized ge indicates that one of the pairs of cutter heads is a double cutter head pair is formed and the two knife levels of the top Double knife head divergent in the running direction of the film web are aligned. 6. Device according to claim 5, characterized in that the two knives ( 11 ) of the double knife head are mounted on an axis ( 60 ) which is bent in the running direction of the film web. 7. Device according to one of claims 1 to 6, characterized in that the lower cutter heads ( 22 - 25 ) are equipped with knives ( 13 ) whose cutting angle β at the cutting edge ( 13 a) is less than 90 °. 8. Device according to one of claims 1 to 7, characterized in that the ends of the rods ( 2 ) and threaded spindles ( 4 , 5 ) on two parallel cheeks ( 1 ) are fixedly attached and from the cheeks ( 1 ), rods ( 2 ) and threaded spindles ( 4, 5 ) formed frame with the cutter heads relative to a stationary base frame ( 19 ) can be moved in the X direction. 9. Device according to claim 8, characterized in that between the cheeks ( 1 ) two rods ( 17 ) are attached, four bearing blocks ( 18 ) are mounted on a stationary base ( 19 ), in which the rods ( 17 ) are axially displaceably mounted , And that on the substructure ( 19 ) a motor ( 70 ) is attached to which a shaft ( 75 ) is drivingly connected, the thread deende ( 75 a) with a threaded bore of the adjacent cheek ( 1 ) is engaged. 10. Device according to one of claims 1 to 9, characterized in that on the carrier plates ( 3 ) of the upper knife heads means ( 80 , 81 ) for mounting blade holders ( 82 ) are hen vorgese. 11. The device according to claim 10, characterized in that each blade holder ( 82 ) by a pneumatic adjustment drive ( 92 ) between a cutting position and an outer cut position is pivotable. 12. A method for retracting the upper knife of a pair of knives in the cutting position, in which it cuts the film web together with the lower knife of the pair of knife heads, in a longitudinal cutting device according to one of claims 1 to 11, characterized in that
the disengaged upper knife ( 11 ) with X distance from the cutting edge ( 13 a) of the lower knife in the direction of the Z-axis in the film web and thereby separates the film web,
then the upper knife in the direction of the Z-axis again to the height position required for its employment on the lower knife and
then adjusted in the direction of the X axis until the cutting position on the lower knife ( 13 ) and the desired contact pressure are reached. 13. The method according to claim 11, characterized in that the movement of the upper knife ( 11 ) takes place pneumatically. 14. A method for adjusting the zero point of a pair of knives in a longitudinal cutting device according to one of claims 3 to 11, characterized in that
the disengaged upper knife ( 11 ) at a distance from the cutting edge ( 13 a) of the running lower knife ( 13 ) in the Z-axis to the cutting height and
then motorized in the direction of the X axis until it touches and is carried along by the lower knife ( 13 ), whereby the drive motor ( 8 ) of the upper cutter head ( 10 ) is switched off.