EP0088885A1 - Feeder for sheet handling machines - Google Patents

Abstract

A sheet feeding assembly for a printing press including a feed table having a set of front stops and which is inclined downwardly so that a sheet travels toward the front edge of the table where it is temporarily retained in registered position. A port connected to a source of compressed air extends through the table at a position spaced from the front edge of the table. A rear feed plate is seated on the table upstream of the port and a front feed plate is seated on the table downstream of the port, the plates being substantially coplanar with their respective front and rear edges in proximity and uniformly spaced with respect to one another. The front edge portion of the rear feed plate is undercut to form an overhang which defines a transversely extending air conducting cavity which overlaps the port so that an air blast is directed at an angle upwardly and forwardly of the table to lubricate the passing sheet and to urge the sheet in the direction of the front stop. The rear plate is adjustably shiftable to vary the spacing between the plates thereby to vary the rate of discharge of the air. A manually adjustable cam elevates the front edge of the rear plate to a variably upraised position thereby to vary the angle of discharge of the air against the sheet.

Description

The invention relates to a sheet application device according to the preamble of the first claim.

A device of this type is described in DE-PS 1 186 473. There are individual slits or a continuous slit across the width of the sheet in the sheet running direction behind the side marks and in front of the cover marks of the sheet placement device. The slots are tight and let the air blow out almost parallel to the sheet feed table, which should hold the sheet down in this area due to the blow-suction effect and at the same time drive it forward. The blown air jets can also be inclined towards the edge regions of the arch in order to tighten the arch. The blown air is controlled centrally by the air supply. The disadvantage of this device is that it is not easily adaptable to different conditions, such as those that occur primarily due to different substrates. No differences can be taken into account regarding the transverse expansion of the paper sheets if they only occur during operation. Finally, the smooth contact sheet creates a strong air cushion from the flowing blown air, especially with light paper types, and the effectiveness of the device is reduced.

A sheet lay-up device is similarly constructed, which is described in US Pat. No. 3,370,847. Nozzles are arranged on the likewise smooth contact plate, which are blown with air. However, they are set at an angle between 5 and 45 ° against the plane of the contact plate, which is made dependent on the paper quality. The A experience has shown that individual nozzles must be permanently set before operation, which is disadvantageous for changes in the operating conditions. The main disadvantage is that limited nozzles are used, which then also act on the paper sheet at limited locations and are difficult to set correctly for light but also heavy papers. Another disadvantage is the use of a smooth surface on the sheet feed table in the area of the nozzles because of the air cushions that then occur strongly.

DE-OS 2 638 784 also describes a sheet feed table whose plate consists of a pattern-rolled sheet, but which is only used for reasons of friction and the air standing in the recesses. Finally, the sheet feed table does not show any blow-suction elements for holding down the sheets.

All of the devices mentioned have the disadvantage that they are difficult to adapt to different substrates and operating conditions. Above all, it is problematic that in the case of changes to the paper, such as, for example, in the case of edge ripples, which can occur sporadically during operation, the blowing-suction effect cannot be adjusted immediately to the new conditions. However, it is important to place the sheet on its leading edge in good time and precisely on the front marks so that it can also be passed on to the subsequent processing machine, such as a printing press, with a perfect fit. This function must also be retained when using different sheet materials and changing operating conditions.

The object of the invention is therefore to provide a device according to the preamble, which makes it possible to improve the sheet transport over the feed table in the area of the front marks with the most varied sheet materials and different operating conditions. It should be able to be adjusted during operation and ensure that the sheet fits snugly against the front marks even if the sheet materials are not uniform. At the same time, the separation of sheets lying one above the other is to be supported.

The solution to the object is found in accordance with the invention in that at least one edge of the slot is adjustable in the plane of the sheet feed table and vertically thereto and that the contact sheet between the air slots and the front marks is provided with a uniform profile. This ensures that the volume flow and the outlet angle of the blown air jet can be changed by changing the slot in the contact plate. With the volume flow, the suction effect in the vicinity of the jet normally changes and with the exit angle, the proportion of the blowing air advancing in the direction of the front marks is determined. The setting can also be changed during operation and quickly adapted to sudden changes, for example of the paper. The arrangement of a profiled sheet between the slots and the front marks is particularly advantageous because the blown air can flow into the depressions of the sheet pattern and the paper thus lies on a weaker air cushion that can be metered more easily. The setting range for the effect of the blown air is thus improved and the area of application of the device is expanded at the same time.

The design of such a device is described by way of example below and shown in drawings.

• Fig. 1 einen Längsschnitt durch die Vorrichtung mit den Stelleinrichtungen,
• Fig. 2 eine Aufsicht auf die Vorrichtung entsprechend ihrer Anordnung in einer bogenverarbeitenden Maschine,
• Fig. 3 eine vergrößerte Darstellung des Ausschnittes X in Fig. 1,
• Fig. 4 eine zweite Ausführung der Vorrichtung im Ausschnitt X der Fig. 1,
• Fig. 5 eine Gesamtansicht des Bogenanlegetisches im Seitenriß,
• Fig. 6 eine Bildfolge mit den Verstellmöglichkeiten am Schlitz und den erreichbaren Richtungen des Blasluftstrahls.

The drawings show in detail in

• 1 shows a longitudinal section through the device with the adjusting devices,
• 2 is a plan view of the device according to its arrangement in a sheet processing machine,
• 3 is an enlarged view of the detail X in Fig. 1,
• 4 shows a second embodiment of the device in section X of FIG. 1,
• 5 is an overall view of the sheet feed table in side elevation,
• Fig. 6 shows an image sequence with the adjustment options at the slot and the directions of the blowing air jet.

The exemplary embodiment in FIG. 1 shows the arrangement of the sheet feed table 1 together with the fixed contact sheet 2 and the movable contact sheet 3. The fixed contact sheet 2 is located near the front marks 4 on the rear edge of the sheet contact table 1 as seen in the direction of sheet travel. The movable contact sheet 3 is moved through Bolts 5, springs 6 and nuts 7 connected to the sheet feed table 1. The bores 8 in the sheet feed table 1 have a larger diameter than the bolts 5 and thus allow the bolts 5 to move when the contact plate 3 is adjusted. The adjustment in the Height is made with setting cams 9 via setting pins 10. The adjusting cams 9 are firmly seated on a shaft 11 which extends over the entire width of the device and can be rotated with the aid of a worm drive 12, 13. The worm 12 is rotated from the handwheel 14 and moves the worm wheel 13 and with it the shaft 11. By rotating the shaft 11, the actuating cam 9 is moved relative to the actuating pin 10 and presses it up against the contact plate 3. This becomes, on the one hand, itself bent and on the other hand slightly raised in the spring-loaded mounting 5, 6, 7. When the control cam 9 is turned back, the contact plate 3 springs back into the starting position. The movement of the contact plate 3 in the plane of the sheet feed table 1 is carried out via a connector 15 which is attached to the contact plate 3. In the connector 15, a set screw 16 is screwed, which is axially fixed relative to the sheet feed table 1. When the adjusting screw 16 on the handwheel 17 is rotated, the connecting piece 15 and with it the contact plate 3 are correspondingly displaced parallel to the plane of the sheet feed table 1. The amount of adjustment of the contact plate 3 is indicated by pointers 18 via scales on the handwheels 14, 17. The horizontal end position of the contact plate 3 is fixed by a safety device 16a in the thread of the set screw 16. 2 shows the arrangement of the contact sheets 2, 3 on the sheet feed table 1. The slot S lies between the front marks 4 and the side marks 19, which are only indicated here. The contact plates 2, 3 are divided into four elements 2.1, 2.2, 2.3, 2A and 3.1, 3.2, 3.3, 3A. The movable contact plates 3.1, 3.2, 3.3, 34 were moved by two setscrews 16 over connecting pieces 15 in order to set the slot S in the plane of the sheet feed table 1. The setting can be done asymmetrically, so that the opening of the slot S a becomes larger on the sides. Likewise, a different contour of the slot S can be set over the arc width. The shaft 11 for adjusting the setting cams 9 and the setting pins 10 on the contact plates 3.1, 3.2, 33, 3A lies parallel to the slot S under the sheet feed table 1. The entire device is in turn arranged parallel to the sheet feed 20 of a sheet processing machine 21. Means for pre-aligning the conveyed sheets can be operated in the cutouts 22 in the contact sheets 2, 3. The sheets are moved in the direction of the arrow over the sheet feed table 1.

3 shows a detail X from FIG. 1 on an enlarged scale. The contact plate 2 is fastened on the sheet feed table 1. The position of the contact plate 3 on the sheet feed table 1 is determined by the set screw 16 via the connecting piece 15 and by the setting cam 9 via the setting pin 10. The maximum adjustment is indicated by dashed lines. A second embodiment in the same section of FIG. 3 is shown in FIG. 4. The contact plate 3 'is rigidly attached to the sheet feed table 1'. The contact plate 2 'is fastened movably on the sheet feed table 1' with the aid of the bolt 5 ', the spring 6' and the nut 7 '. The sheet feed table 1 'is worked across its width in the area of the contact plate 2' obliquely against the sheet running direction. The contact plate 2 'is drawn into this recess by the spring 6'. If the actuating cam 9 'is now rotated and pushes the actuating pin 10' up, the contact plate 2 'is also lifted up to the dashed position in the plane of the sheet feed table 1'. The adjustment of the contact plate 2 'in the plane of the sheet feed table 1' is carried out with set screws 16 'by turning in a connecting piece 15'. The end position is in the Ge by a fuse 16a ' winch the tie rod 16 'set.

In both versions, it should be noted that a pattern-rolled sheet, which is arranged with its convex side having elevations, has proven to be advantageous for the contact sheet 2, 2 '.

The bolts 10, 10 'and the connecting pieces 15, 15' are riveted, screwed or welded onto the contact plates 2 ', 3, the projection welding method would probably be preferable. The height adjustment of the one slot edge does not have to be carried out via a setting cam 9. Lever drives or wedge elements also serve the same purpose.

The blown air is continuously fed to the slot S. A cutout 23, 23 'is provided in the contact plate 3, 3', to which holes 24, 24 'in the sheet feed table 1, 1' are assigned. These holes 24, 24 'are evenly distributed over the entire width of the sheet feed table 1, 1' and can be provided with connections 25 for the air supply as shown in FIG. 1. Each connection can be provided with a valve for throttling the blown air flow.

The change in the blown air flow at slot S with constant air supply and adjustment of a slot edge is shown in FIG. 5.

End positions of the individual adjustment devices are combined with each other for this purpose. Fig. 5A shows the narrowest position of the slot S. the blowing air from the Bore 24 is deflected in the cutout 23 and emerges very steeply upwards due to the narrow position of the slot S. Only the kinetic energy from the horizontal deflection in the cutout 23 tends the beam approximately to the left. 6B, the slot S is fully opened horizontally by moving the contact plate 3 to the right. The blown air then emerges somewhat obliquely due to the enlarged slot opening and acts more in the direction of the gust. In addition, the exit speed is lower because a larger volume could now flow through the now larger opening. `As a result, the pressure difference at the slot becomes smaller and, in proportion, the outflow speed. This characteristic is due to the falling characteristic curve of the centrifugal compressors most commonly used on sheet-processing machines for air supply and is also desired here. The negative pressure that builds up the most at the edge of the slot S relative to the contact plate 3 depends on the exit velocity and the exit angle of the blown air jet. Thus, by changing the characteristic of the blown air jet via the slot opening, the suction effect on an arc running through the slot S can be adjusted.

The representation in FIG. 5C shows the edge of the contact plate 3 in its maximum height above the sheet feed table 1. The blown air now exits the slot S at an angle. The opening corresponds approximately to the case from FIG. 5B, since the adjustment path of the contact plate 3 is a maximum of 1 mm in both directions. Due to the stronger inclination of the blown air jet, the effect is now directed even more in the direction of sheet travel. This effect is strongest at maximum opening of the Slot S as shown in Fig. 5D. The blown air jet emerges almost parallel to the surface of the sheet feed table 1 and thus takes the sheet most strongly in the direction of the front marks 4. In this case, the profile of the negative pressure in the vicinity of the blown air jet is very flat, thus showing a defined alignment with the front marks 4 there. The importance of using the pattern-rolled sheet becomes important here. The air that is blown under the bow makes it float on a smooth surface. When using a pattern-rolled sheet as contact sheet 2, however, the blown air can at least partially escape through the depressions in the sheet pattern. This results in the effect that the sheet is easily guided over the elevations of the sheet as required by the slot setting and is therefore easier to control. In addition, it is not so easy to flutter and whistle the edges of the arch, since the excess blowing air can flow away. The sheet metal pattern is of course not necessarily limited to a concave-convex configuration, since other patterns are also conceivable with which the above-described effect can be achieved, such as groove patterns, diamond patterns or snake patterns. The type of sheet is also not limited to rolled sheet, and sheets or cast semi-finished products can also be used.

FIG. 6 provides an overview of the entire sheet feeding device with sheet feeding table 1, contact sheets 2, 3, front marks 4, side marks 19, slot S and air supply path 24, 25. For thin or electrostatically reacting sheets in special situations materials, it is necessary to separate the sheets of a shingled incoming sheet stream 26, which is transported by belts 29, from one another. It can happen there that the first upper sheet when it is transported into the sheet-processing machine 21 pulls the next lower sheet a little bit before it is held by the suction effect of the slot S, and thus the system on the front marks 4 is uncontrolled. The adhesive effect of the two sheets can be reduced by arranging blowers 28 on the frame 27 above the sheet feed table 1 and setting these blowers 28 behind the trailing edge of the sheet when the sheet is in contact with the front marks 4. They then blow air from behind under the upper arch, creating a slight arch separation between the first upper and the next lower arch.

• Ein Bogenstrom 26 läuft über den Bogenanlegetisch 1 von den Förderbändern 29 getragen. Bei Erreichen des Schlitzes S wird die Vorderkante des ersten Bogens von der Sogwirkung im Umfeld der Blasluft erfaßt und niedergehalten. Wellen im Bogenmaterial werden beseitigt und der Bogen wird durch. die Transportwirkung des Blasluftstroms an die Vordermarken 4 geführt. Bei Erreichen der Vordermarken kommt die Hinterkante des Bogens in den Bereich der Bläser 28 und wird mit Luft angeblasen. Die Luft tritt auch unter den Bogen und trennt den ersten oberen vom nächsten unteren Bogen, so daß nicht mehr die Gefahr des Überrollens am unteren Bogen beim Abziehen des oberen Bogens besteht.

The sheet run then looks like this:

• A sheet stream 26 runs over the sheet feed table 1 carried by the conveyor belts 29. When the slot S is reached, the front edge of the first sheet is gripped and held down by the suction effect in the vicinity of the blown air. Waves in the arch material are removed and the arch is through. the transport effect of the blown air flow to the front brands 4. When the front marks are reached, the rear edge of the sheet comes into the area of the blower 28 and is blown with air. The air also passes under the arch and separates the first upper arch from the next lower arch, so that there is no longer any danger of rolling over the lower arch when the upper arch is pulled off.

The blowing and suction effect at slot S can be adjusted to different operating conditions. Thin sheet materials require less suction. Thick sheet materials, such as cardboard, require greater suction and, because of their weight, also greater propulsion to the front brands. In poorly air-conditioned sheet stacks, malfunctions due to electrostatic effects or paper deformation occur during sheet processing. As described, all of these preconditions must also be met during operation by adjusting the slot S.

Of course, a basic adjustment of the blown air flow, which must be carried out before the sheet feeder is operated, can also be carried out on the valves of the air feeds 24, 25. This can be the case for extreme differences in sheet material. A separate setting on the edge of the sheet may also be necessary to prevent flutter. Above all, any obstacles in the form of alignment elements can be observed.

The joint adjustment of the two edges of the slot S by levers which are firmly connected on both sides can also be advantageous in such a way that one slot edge is moved up and the other is moved downwards by tilting one lever.

Claims (7)

1.) Sheet application device on sheet-processing machines with a sheet feed table and front marks for precisely fitting the sheets at the front edge, one or more blows to which blowing air can be applied being arranged at a distance from the front marks in the sheet feed table in the direction of sheet travel.
characterized
that the slot (S) actuators (9 to 18) are assigned to change the opening in size and shape and thus the direction and volume flow of the blowing air jet can be influenced and that the sheet-guiding surface of the sheet feed table (1) between the slots (S) and the front marks (4) is provided with a uniform profile. 2.) Device according to claim 1,
characterized,
that the slot (S) forming contact sheets (2, 3) of the sheet feed table (1) each in one piece or more Parts are that the slot (S) is formed by a fixed and a movable edge, that the first edge of the slot (S) seen in the sheet running direction by adjusting devices (9, 10) vertically to the level of the sheet feed table (1) in height above from its horizon and by further adjusting devices (15, 16), also at a distance from the second fixed edge of the slot (S) in the plane of the sheet feed table (1), the movable contact plate (2) forming a cavity (23) the bottom of its edge is milled towards the slot (S). 3.) Device according to claim 1,
characterized,
that the slot (S) forming contact sheets (2 ', 3') of the sheet feed table (1 ') are each in one piece or in several parts, that the slot (S) is formed by a fixed and a movable edge, that the second seen in the direction of sheet travel Edge of the slot (S) by adjusting devices (9 ', 10') vertical to the plane of the sheet feed table (1 ') below its horizon and by additional adjusting devices (15', 16 ') also at a distance from the first, fixed edge of the slot ( S) can be adjusted in the plane of the sheet feed table (1), the fixed contact plate (2 ') being milled towards the slot (S) on the underside of its edge to form a cavity (23'). 4.) Device according to claim 1, 2 or 3,
characterized,
that the contact plate (2, 2 ') between the slot (S) and the front marks (4) be made of pattern-rolled sheet stands and the pattern-rolled sheet has a concave side with depressions and a convex side with elevations, that the contact sheet (2, 2 ') is arranged with the convex side up, that the top of the edge of this sheet at the slot (S) is broken or is cut along deep-lying zones of the sheet metal pattern. 5.) Device according to claim 2 or 3,
characterized,
that the adjusting devices for adjusting the slot edges vertically to the plane of the sheet feed table (1) from a worm drive (12, 13) of a shaft (1) with a plurality of adjusting elements (9, 9 ') and transmission elements (10, 10') between the adjusting elements (9 , 9 ') and the contact plate (2', 3) that the shaft (11, 11 ') is arranged parallel to the slot (S) in the sheet feed table (1, 1'), and that the adjustment of the worm drive (12, 13) on a display device (18) indicates the adjustment of the slot edge. 6.) Device according to claim 2 or 3,
characterized,
that the sheets (2 ', 3) forming the adjustable slot edge are each provided with a plurality of connecting pieces (15, 15') over their width, the threaded holes have setscrews (16, 16 in the threaded holes of the connecting pieces (15, 15 ') ') are screwed in, which are fixed relative to the sheet feed table (1, 1') and by their rotation the contact sheets (2 ', 3) forming the adjustable slot edge in the plane of the sheet feed table (1, 1 ') can be adjusted relative to the fixed slot edge. 7.) Device according to one or more of claims 1 to 6,
characterized in that blowing devices (28) are arranged above the sheet feed table (1), blow the air in the sheet running direction against the rear sheet edge and can be adjusted to the format of the sheets processed in each case.

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