EP1112951B1 - Device for contactless guiding a material web - Google Patents

Abstract

The air cushion support device (2) for adjusting the position of a web (22) in the drier of a web-fed rotary printing machine has an air flow adjuster (6), e.g. a plate with air slots (8, 10). This can be moved to adjust the air flow through passages (16, 18) on either side of the device.

Description

The present invention relates to a device for contactless guidance Material web, in particular an air rod for contactless guidance Material web in a dryer of a web-fed rotary printing press, according to the Preamble of claim 1.

In US 5,353,979 is a guide device for guiding, deflecting and / or deflecting one Material web described. The guide device for guiding, deflecting and deflecting one A material web, which is guided over a plurality of rollers, comprises a block which is connected to a Medium supply device is connected, which supplies the block with a medium (air). The block has a curved surface over which the web can be guided and a plurality of holes in each of the separate sections forming the block having. The sections run across the material web. There is one for the material web A large number of separate sections are provided, which form a medium bed for the material web form. Supply lines that run along the separate sections run through the block connect the medium supply device, the medium from the Medium supply device starting from the supply lines from the Bores can flow out against the material web. Are in the supply lines Control valves arranged outside the block, by means of which the speed and the volume of the medium flow into the respective supply line can be controlled, so that a different pressure can be applied to each separate section. In this way a pressure drop across the width of the web is formed so that the web depending on the pressure gradient that forces the web away from the block surface, deflected and deflected from a first guided direction into a second guided direction can be.

A steerable air device is described in US Pat. No. 5,152,080. The device supports a web non-contact and keeps the web in a substantially straight path, while moving through the dryer. The device comprises a steerable Air bar arrangement with at least one adjustable air bar, which is an extended one Has surface from which air can escape. The extended surface is in opposite ratio to the running path and has two ends. Further are one that is in flow communication with the air rods Air supply device and an actuator for changing the orientation of the extended surface of the adjustable air rods with respect to the running Material web provided. In a preferred embodiment, the surfaces set in such a way that each of the surfaces rotates about an axis which in the Runs essentially parallel to the center line of the running web. The dirigible Air bar arrangement is arranged in a dryer in such a way that the web in the Is essentially straight through the dryer. In a dryer one can A variety of such steerable air bar assemblies can be provided. The dryer can also comprise a fixed air rod or a plurality of fixed air rods. The Air rods can include counter pressure devices for generating a counterforce, which move the web back to a substantially central position. The Back pressure device preferably comprises one or more edge attachments Edge attachments, which are preferably at the ends of the fixed air rods or in the Near the ends of the fixed air rods are arranged in the dryer.

An air rod is already from document JP 11-165 924 A. to change the position of a material web according to The preamble of claim 1 is known.

The need to divert webs arises when webs are sideways have varying tension characteristics, are shifted laterally while they moved through a dryer section, e.g. with a static path shift. A web shift can be made after passing through the dryer section by means of a commercially available web guiding device or immediately when it occurs in Dryer section can be compensated. In some cases, the shift of the However, the web in the dryer is too large for a correction by the web guiding device his.

Accordingly, it is an object of the present invention to provide an apparatus for non-contact steering of material webs in units of printing machines create, by means of which the disadvantages of known devices described above Kind be eliminated and changes in pressure drop across the width of one Air rods assigned to the web guide level. It is also a task of present invention, a lateral displacement of webs with laterally varying To compensate for voltage properties.

This object is achieved by the features of claim 1.

Further features of the present invention are contained in the subclaims.

An air rod according to the invention for guiding a material web, i.e. to change the lateral position of the material web, comprises an air rod body with one in it formed hollow interior, which used to form an air cushion under the material web Compressed air can be applied. To control the air flow and thus to control one lateral direction of movement of the material web is at least one air duct with the hollow interior connected. The hollow interior is a metering device assigned, which is arranged in such a way that the from the at least one air duct outflowing air flow is optionally limited.

The solution according to the invention offers numerous advantages. By side correction Web shifts already in the dryer can be used for additional web guiding devices omitted or simplified, since no strong after leaving the dryer lateral deviations of the web occur more. Therefore, with some Applications web guide devices downstream of the dryer unnecessary because the Path shifts can already be corrected in the dryer. The Air rods according to the invention are preferably above and below the web guide level arranged.

According to a further embodiment of the device according to the invention, the Metering devices are preferably substantially horizontal and are in the air bars integrated. The dosing devices essentially run vertically, i.e. in a lateral direction to the material web and preferably extend over the entire width of the material web.

The dosing devices integrated in the air rods allow the Dosing devices with respect to the air channels arranged on the air rod bodies. The dosing devices are movably arranged so that they have a relative movement can perform with respect to the air channels or openings, which are preferably fixed predetermined positions are arranged on the air rods.

In an alternative embodiment, by rotating the metering device into a first direction (e.g. clockwise) by a preferably perpendicular to the plane of the path running pivot axis the degree of coverage between the openings on a Side of the air rod is raised and reduced on the other side of the air rod, the air flow emerging from the air channels on one side being amplified and the air flow emerging on the other side is reduced. Through these different Air currents and the pressure drop thus created can move the web sideways, i.e. lateral, or be moved perpendicular to the web guide direction. When the Dosing devices in a second direction (e.g. counterclockwise) around the Pivot point, or the pivot axis, the degree of coverage between the Openings are reduced on one side and increased on the other, being the airflow flowing out of the air channels on one side is reduced and on the other other side is increased. In this case the web of material is in the opposite shifted to the side.

The present invention further provides another embodiment in which the Dosing device for changing between the edges of the dosing device and the adjacent side walls of an air rod body formed, the air channels forming columns around a preferably essentially pointing in the web running direction and / or one pointing perpendicular to the web running direction within the web plane Swivel axis is movable. To move the metering device are preferred Adjusting elements are provided, by means of which the shape of the between the metering device and the side walls of the air rod body formed column can be changed. On in this way, the total air currents emerging from the air channels and the Air flows emerging from each side of the air ducts are controlled so that a lateral displacement of the material web is achieved.

In a further embodiment, along the width of the material web Spacers can be provided over the air rod through which the air channels from each other are spaced. Air exchange openings are preferably on the metering device and control openings arranged, which change the air pressure in the under can produce air cushions generated in a web guide plane. To adjust the device, control openings are preferably provided, which with the openings for controlling an outflow channel formed in the air rod outflowing air flow can be brought into overlap. The tax openings can be operated manually, mechanically or electrically, d. H. be moved.

The air rods according to the invention can, for. B. in devices for contactless Transport of web-shaped material or assigned in rotary printing machines Dryers are used.

The features of the present invention will become apparent in the following description preferred embodiments in connection with the accompanying, below listed drawings explained in more detail.

Fig. 1a

eine schematische Seitenansicht einer erfindungsgemäßen Luftstange mit einer unter Luftkanälen angeordneten Dosierplatte und dieser zugeordneten Dosieröffnungen;

Fig. 1b

eine Draufsicht einer erfindungsgemäßen Luftstange mit Dosierplatte;

Fig. 2a

eine Seitenansicht eines um einen in der Luftstange angeordneten Schwenkpunkt schwenkbaren Dosierventils;

Fig. 2b

eine perspektivische Abschnittsansicht des in Fig. 2a gezeigten Dosierventils;

Fig. 3a

eine Seitenansicht von einem Abströmkanal zugeordneten Dosieröffnungen mit den Dosieröffnungen zugeordneten, auf diese zu bewegbaren Steueröffnungen;

Fig. 3b

eine Draufsicht eines Abschnitts der Vorrichtung nach Fig. 3a, bei dem die Steueröffnungen auf die ortsfesten Dosieröffnungen zu gedreht wurden;

Fig. 3c

eine Draufsicht eines Abschnitts der Vorrichtung nach Fig. 3a, bei dem die Steueröffnungen auf die ortsfesten Dosieröffnungen zu verschoben wurden;

Fig. 4

eine perspektivische Abschnittsansicht eines Trockners, in den die erfindungsgemäßen Luftstangen oberhalb und unterhalb der Bahnführungsebene integriert sind;

Fig. 5

eine Seitenansicht einer erfindungsgemäßen Luftstange, die sowohl die Dosierplatte mit den dieser zugeordneten Dosierspalten als auch die dem Abströmkanal zugeordneten Dosieröffnungen umfasst.

Show it:

Fig. 1a

is a schematic side view of an air rod according to the invention with a metering plate arranged under air channels and metering openings associated therewith;

Fig. 1b

a plan view of an air rod according to the invention with a metering plate;

Fig. 2a

a side view of a metering valve pivotable about a pivot point arranged in the air rod;

Fig. 2b

a perspective sectional view of the metering valve shown in Fig. 2a;

Fig. 3a

a side view of an outflow channel associated metering openings with the metering openings assigned to them to move movable control openings;

Fig. 3b

a plan view of a portion of the device of Figure 3a, in which the control openings have been rotated towards the stationary metering openings.

Fig. 3c

a plan view of a portion of the device of Figure 3a, in which the control openings have been moved to the fixed metering openings.

Fig. 4

a perspective sectional view of a dryer, in which the air rods according to the invention are integrated above and below the web guide plane;

Fig. 5

a side view of an air rod according to the invention, which comprises both the metering plate with the metering gaps assigned to it and the metering openings assigned to the outflow channel.

In all drawings, the same elements are denoted by the same reference symbols. In Fig. 1a and 1b, an air rod 2 is shown with a metering plate 6, which is below the Air channels 16, 18 arranged metering gaps 8, 10 are assigned.

The air rod 2 shown in a side view comprises one with compressed air actable hollow interior 4. A carrier 24 is arranged above the air rod 2, through which the first air duct 16 is spaced from the second air duct 18. The Air channels 16 and 18 can be as a continuous column or as a series of one another bordering holes can be formed. The essentially horizontal one Dosing plate 6 is arranged in the hollow interior 4 of the air rod 2. The dosing plate 6 is around a housing surrounding the hollow interior 4 of the air rod 2 arranged pivot point 12 movably attached. In an edge section of the Dosing plate 6, this is an adjusting element 14, which is a relative movement of the Dosing plate 6 with respect to the air channels 16 and 18 allows. The pivot point is 12 preferably on an imaginary center line of a processing station, e.g. B. one Dryer, arranged through which a material web 22 is guided. By pressing the Actuator 14, the z. B. as a manually, mechanically or electrically operated Can be formed lever, the relative position of the metering plate 6 is in the direction of Air channels 16 and 18 easily adjustable. The dashed line in Fig. 1b indicates an electrical or mechanical, especially hydraulic or pneumatic drive 108, which drives the actuator 14. As in Figures 1a and 1b is shown, a pivoting movement of the metering plate 6 clockwise around Pivot point 12 to reduce the air channels 16, 18 from one end escaping airflow as well as an increase in air flow from the other end of the Air channels 16, 18 exiting airflow during a pivotal movement of the Dosing plate 6 counterclockwise a reverse distribution of the air flow to the Ends of the air channels 16, 18 causes.

This leads to an increase in the flow rate at the ends of the air ducts 16, 18 to increase the speed and volume of the airflow so that the air pressure of the air cushion 20 formed under the transported material web 22 one side of the material web 22 rises. In Fig. 1a is a side view of the under Material web 22 formed air cushion 20 shown. The direction of transport of the Material web 22 is indicated by the arrow at the end of material web 22. By the Using the metering plate 6, the flow rates of the air channels 16, 18 can be varied so that to adjust the lateral (perpendicular to the transport direction of the web running) movement of the web different pressure drops can be generated.

In Fig. 1b the dosing plate 6 already shown in Fig. 1a is shown in detail.

In the top view of the metering plate 6 according to FIG. 1b, the pivot point 12 is shown around the the metering plate 6 can be pivoted by actuating the control element 14. In the The embodiment of the metering plate 6 shown here runs the metering gaps or Air exchange openings 8, 10 from a drive-side section 26 of the metering plate 6 to an operator-side section 28, i.e. in the lateral direction to the direction of movement of the material web 22. The dashed line denotes the openings of the air channels 16 or 18, which are either completely congruent with the columns 8, 10 of the metering plate 6 or more or less depending on the relative position of the metering plate 6 are closed. The openings of the air channels 16, 18 can be a continuous gap or be formed as a series of bores. The arrow in Fig. 1b shows the Transport direction of the material web 22. In this way, the material web 22nd shifted sideways in addition to their movement along their normal transport path, by amplifying the air flow flowing out of one end of the air channels 16, 18 and the air flow flowing out of the other end of the air channels 16, 18 is reduced.

In the embodiment according to FIG. 1b, sensors 110 are arranged above the carrier, which determine a position of the web 22 with respect to the air rod 2. The sensors 10 are connected to a control unit 112, which in turn is connected to the drive 108 Control of the actuator 14 is connected. This way the position of the web 22 depending on whether a control or regulating device is used, automatically controlled or regulated.

2a and 2b is a second embodiment of the device according to the invention shown, which is pivotable about a pivot point arranged in the air rod 2 Dosing valve 40 includes.

According to this embodiment is also an adjustment of the openings of the respective air duct 16, 18 outflowing air flow possible. The air rod 2, the comprises an air rod body 36, is on an imaginary center line Processing station, e.g. B. a dryer arranged. The air rod body 36 includes a hollow interior 4, which can be acted upon by compressed air. In the hollow interior 4 the air rod 2, a metering valve 40 is arranged. Is above the metering valve 40 Carrier body 38 arranged through which the air channels 16, 18 spaced apart are. The carrier body 38 is fastened to the metering valve 40 via bellows 100. About that Carrier 38 and the air channels 16, 18 is the material web 22 under which the Air cushion 20 is formed. The dashed lines indicate a deflection plane 34 of the web on. The air channels 16, 18 are between the outer walls of the air rod body 36 and arranged obliquely extending side portions of the carrier body 38. The Edge sections of the metering valve 40 are preferably the same in comparison with the arranged oblique wall sections of the air rod body 36 and form in this way the air channels 16, 18 between the respective side edge and the respective wall section.

At one end of the air rod body 36 (see FIG. 2b) are on an imaginary center line of the air rod body 36 a pivot point and an actuator 46 for adjusting the Dosing valve 40 arranged. The actuator 46 allows movement of the Metering valve 40 in such a way that one end of the metering valve 40 in the region of a first Edge of the material web 22 with respect to the other end of the metering valve 40 in the area the opposite side or edge of the material web 22 raised or lowered becomes. Downward movement of the metering valve 40 causes the oblique Side edges of the metering valve 40 in the direction of the likewise oblique wall sections of the Air bar body 36 moves so that the width of the metering column 42, 44 at one end the air rod 2 is reduced and enlarged at the other end. By an up or Downward movement of the metering valve 40 can increase the flow rate of the metering gaps 42, 44 can be controlled. The embodiment shown in FIGS. 2a and 2b also enables an oblique arrangement of the metering valve 40 by the first actuating element 48 upwards rotated and the second actuator 50 is rotated downward. Accordingly, it will Metering valve 40 pivoted about its central attachment point, with a metering gap 42 is opened further than the opposite metering gap 44. In this way on the air duct 16 and on the air duct 18 in a simple manner different Flow rates are achieved, which e.g. the position of the maximum Curvature of the web path in the direction of movement of the material web 22 can be changed.

The first and the second actuating element 48, 50, which are shown here by way of example, each preferably comprise a rod-shaped element 52 which extends over a respective one Fastening element 54 is connected to the metering valve 40. An actuation of the middle control element 46 and the adjacent control elements 48, 50, through which a If the dosing valve 40 is tilted, e.g. manually via a (Turn) knob or another type of adjusting element. For remote control of the Actuators 46, 48, 50 can be any of the actuators 46, 48, 50, e.g. an electric motor or be associated with a similar device that has a default depending of the material to be processed or different pressure drops across the width of the made possible, for example, by a dryer web 22. The Dosing gaps 42, 44 can be a gap-shaped opening section or one of one Have a plurality of holes or bores formed opening portion.

FIG. 3a shows a third embodiment of the present invention, which consists of an outflow channel 56, preferably circular metering openings 58 is formed. The metering openings 58 comprise control elements 60 which are in the direction of the Dosing openings 58 are arranged movably.

In the embodiment according to FIG. 3a, the air rod 2 with its hollow interior 4 shown. The hollow interior 4 is pressurized with compressed air and includes the Outflow channel 56, which is formed in a metering body 104. Adjacent to the The outflow duct 56 contains the first air duct 16 and the second air duct 18, their Openings run obliquely in the direction of the outflow channel 56. The air channels 16, 18 are between oblique or inclined wall sections of the air rod body 36 the air rod 2 and preferably in a corresponding manner obliquely or inclined extending portions of the metering body 104 arranged, the outflow channel 56th Are defined. However, the cross section of the respective air duct 16, 18 preferably remains constant over its entire length.

In Fig. 3a is another method for changing one of the air rod 2 away directed airflow shown. In the previously described embodiments, the Air flow flowing to the air channels 16, 18 through the openings 8, 10 of the metering plate 6 or the metering gaps 42, 42 of the metering valve 40 changed. In the embodiment 3, the air flow flowing to the air channels 16, 18 is not necessary Way changeable. The dosing body 104 comprises a plurality of side by side arranged metering openings 58 of predetermined size. Under the metering openings 58 is control element 60 either displaceable and / or about pivot point 12 pivotally arranged.

As shown in FIG. 3a, it is from the air channels 16, 18 under the material web 22 outflowing airflow either an outward airflow 64 which is at the Generation of a load-bearing air cushion under the material web 22 primarily involved is, or an inward airflow 62 that is not or only in a small amount Dimensions involved in the generation of the air cushion under the web 22. In Depending on the degree of opening determined by the control elements 60 Dosing openings 58 in the dosing body 104 can only be the inward air flow 62 to a limited extent from the central portion of the air cushion formed under the web 22 Drain 20. Accordingly, that is formed under the central portion of the web 22 Air cushion 20 depending on the position of the control element 60 with respect to the Dosing openings 58. In this way, the height of the material web 22 above the Air rod 2, i.e. the material web is displaced perpendicular to the transport direction of the web become.

The actual position of the control element 60 with respect to the metering openings 58 accordingly determines the inflow of the inward airflow 62 into the Outflow channel 56. This in turn influences the air pressure under the material web 22 formed air cushion 20.

3b and 3c are respectively an enlarged top view of the control element 60 shown, in which a rotational movement (Fig. 3b) and a displacement (Fig. 3c) of the Control element is shown.

3b shows a control element 60 which can be pivoted about the pivot point 12 shown. The double arrow 66 indicates a pivoting movement of the control element 60 at about the pivot point 12. In FIG. 3b, those that open into the outflow channel 56 are Dosing openings 58 of a predetermined size, preferably circular, while the openings 70 in the control element 60 are preferably rectangular are. Through the cooperation between a circular metering opening 58 and one rectangular opening 70 is a steadily increasing opening or closing of the in the Discharge duct 56 leading into outflow channel 56 without a sudden, abrupt Changing the opening size of the metering opening when the control element is actuated 60 allows. In this way, the pressure drop on both sides of the material web 22 can be varied so that a lateral movement of the material web 22 is effected.

3c shows a control element 60 suitable for a sliding movement. In In this embodiment, openings 70 in control element 60 are preferred shaped either square or rectangular. The metering openings 58 of predetermined In this embodiment, sizes are also preferably square. The Arrow 68 in FIG. 3c indicates a sliding movement of the control element 60. The two in 3b and 3c control elements 60 are perpendicular to the transport direction of the Material web 22 aligned. The drive side edge 26 and the operator side edge 28 of the material web 22 in the processing station are also indicated in FIG. 3. On in this way the pressure drop with respect to the ends or sides of the air rod 2 changed and thus a lateral displacement of the material web 22 can be achieved.

The drive 108, the sensors 110 and the control device 112 of FIG. 1b can in the same way as in Fig. 1b also in those shown in Figs. 2a, 2b and 3a to 3c Embodiments may be included.

4 is a perspective view of a dryer 72 with partially removed Exterior walls shown.

The dryer 72 runs from an inlet area 76 to an outlet area 74 the drive side 26 of the dryer 72 are fans, hot air lines and a Line system and the air rods 2 according to the invention arranged. The Air rods or nozzle bars 2 according to the invention are, for example, each other arranged opposite below and above the web conveyor level 102 and here behind the Inlet area 76 shown. There can be one in each section of the dryer 72 Guide device from an upper and a lower air rod 2 may be provided. For the successive sections of the dryer 72 like a heating zone, one Evaporation zone and a cooling zone can each one of the described Guide devices may be provided to guide the material web 22. In this way can a lateral displacement of the material web 22 already in the processing station, i.e. the dryer, can be compensated for, so that the outlet area 74 of the Dryer 72 downstream mechanical web guide can be omitted or the lateral Displacement of the material web can be kept within certain limits, so that the lateral displacement of the web by a mechanical web guide can be compensated.

5 shows a further embodiment of an air rod 2 according to the invention, to control the lateral displacement of the web 22, the metering plate 6 with the the air channels 16, 18 associated metering gaps 8, 10 together with the Dosing openings 58 and the control elements 60 assigned to the outflow channel 56 is used. Through the air rod 2, both the lateral position of the web 22 is through a pivoting of the metering body 104, as well as the height or the profile of the web 22 by opening and closing the metering openings 58 accordingly controlled by Fig. 1a, 1b and 3a-3c already described manner.

List of reference numbers

2

air bar

4

hollow interior

6

dosing

8th

metering

10

metering

12

pivot point

14

actuator

16

air duct

18

air duct

20

air cushion

22

web

24

carrier

26

drive section

28

Operator section

34

deflection plane

36

Air rod body

38

support body

40

metering valve

42

metering

44

metering

46

actuator

48

actuator

50

actuator

52

rod-shaped element

54

fastener

56

outflow channel

58

metering

60

control element

62

inward airflow

64

outward airflow

70

openings

72

dryer

74

exit area

76

intake area

100

bellows

104

metering

108

drive

110

sensors

112

control unit

Claims (11)

1. Air bar (2) for changing the position of a web of material (22), in particular in a drier of a web-fed rotary printing press,
   including an air bar body (36) extending substantially perpendicular to the direction of travel of the web of material (22) and being formed with a hollow interior (4) which extends along the air bar body (36) and through which an air flow for forming an air cushion (20) below the web of material (22) can be fed to an air channel (16, 18) extending along the air bar body (36),
   characterized in that within the air bar body (36), a metering device (6, 40, 60) is arranged, by which the air flow exiting the air channel (16, 18) can be changed across the width of the web of material (22) in such a way that a force is generated that acts upon the web of material (22) in the lateral direction.
2. Device according to claim 1,
   characterized in that the metering device comprises a metering plate (6) and a carrier (24) pivotable about a pivot axis (12) that extends substantially perpendicular with respect to the direction of web travel, the carrier (24) closing off one or more apertures (8, 10, 42, 44) formed in the metering plate (6) and being in flow connection with the air channel (16, 18) to a greater or lesser extent depending on the pivot angle.
3. Device according to claim 2,
   characterized in that the apertures are designed as bores arranged in a row or as a metering slot (8, 10, 42, 44).
4. Device according to one of the preceding claims,
   characterized in that the carrier (24) has an exhaust channel (56) connected to a suction device and a metering aperture (58) arranged below the web of material (22) at least in the region of the air cushion (20).
5. Device according to claim 4,
   characterized in that a plurality of metering apertures (58) is arranged on the side of the metering body facing the web of material (22), the metering apertures (58) being simultaneously increasable or decreasable by sliding a control element (60) having control apertures (70) in a substantially lateral direction in order to change the air cushion (20) below the web of material (22) by increasing or decreasing the amount of air sucked off through the exhaust channel (56).
6. Device according to claim 5,
   characterized in that the control element (60) having control openings (70) is pivotable about a pivot axis (12) extending substantially perpendicular to the web of material (22) in such a way that the amount of air sucked in through the metering apertures (58) is increased on a first side (26) of the web of material (22) and decreased on the opposite side (28) of the web of material (22) depending on the pivoting direction.
7. Device according to one of claims 5 or 6,
   characterized in that the control openings (70) are rectangular and the metering apertures (58) are circular or rectangular.
8. Device according to claim 1,
   characterized in that the metering body has a carrier body (38) that is fixed with respect to the air bar body (36) and a metering valve (40) connected to the carrier body (38) via sealing elements (100), preferably in the form of bellows, the metering valve (40) being suitable to change metering apertures (42, 44) formed between the air bar body (36) and the metering valve (40) and associated with the air channel (16, 18) in such a way that the amount of air in the region of a first side (26) of the web of material (22) can be increased and the amount of air in the region of the opposite side (28) of the web of material (22) can be decreased.
9. Device according to claim 8,
   characterized in that, with the aid of first adjustment elements (46, 52, 54), the metering valve (40) is pivotable about a first axis extending substantially in the direction of the web of material (22) to increase the amount of air passing through the metering apertures (42, 44) on a first side (26) of the web of material (22) and to decrease the amount of air on the opposite side (28) of the web of material (22) correspondingly.
10. Device according to claim 9,
    characterized in that second adjusting means (48, 50) are provided for acting on the metering valve (40) in such a way that, upon an adjustment of the first and second adjustment means, the metering valve (40) is displaceable in the direction of an axis extending substantially perpendicular to the web of material (22) in order to change the total amount of air passing through the metering apertures (42, 44) to increase of decrease the air cushion (22).
11. Device according to claim 10,
    characterized in that the metering apertures are designed as metering slots (42, 44) formed by inclined wall portions of the air bar body (36) and edge portions of the metering valve (40) inclined in the same way and cooperating with the wall portions of the air bar body (36).

Images