EP0987205B1 - Loop buffer for tape material and its use - Google Patents

Abstract

The loop buffer (16,19) accommodates a loop of moving, flexible material between a delivery section in which the material moves at a delivery speed and an output region in which it moves at a different speed. The storage device has a first traction mechanism (335,55) on the delivery side for pulling the material into it and a separate second traction mechanism (35,56) on the output side for pulling the material into the storage device An Independent claim is also included for an embossing arrangement, esp. a heat embossing arrangement.

Description

The invention relates to a storage device for recording a loop section of at least one moving flexible Material web, in particular an embossing film web, between a feed area upstream of the storage device, in which the material web at a feed web speed is moved, and a downstream discharge area in which the at least one material web with an at least temporarily discharge path speed deviating from the feed path speed is moved.

Such storage devices can be of the type of expansion tanks or material buffers are used in one Device for processing the in the form of at least one flexible material web present material areas at least temporarily different material web speeds separate from each other. Adapting the different Speeds can take place in that the Storage device a more or less long loop section the web of material and in this way Speed differences between the supply side and the discharge side compensates without being too compressible or too impermissible Tensile stress on the material web comes.

Known storage devices of this type have a vacuum container, into a loop section of the material web is sucked in. At the entrance area of the vacuum tank the loop section is in two places, for example held on pulleys while the one in between Loop section is tightened by negative pressure. there the more or less deeply drawn loop section works like a piston while the associated cylinder passes through the smooth-walled container walls is formed. To avoid the intake of secondary air must the the web edges facing container walls as close as possible to the edge of the material web be arranged so that the width of a vacuum chamber expediently the width of the stored material web only slightly exceeds. Because the suction chamber is very wide must be adapted exactly to the width of the material web, when changing from a web width to a other storage devices replaced accordingly be converted by manually moving chamber walls, by the chamber width to the width of the new material web adapt. Such vacuum accumulators are, for example from European patent applications 0 176 905 which is considered the closest prior art, or EP 0 623 432 and have proven to be relatively stiff or solid material, such as paper or photographic film material, well proven. It is known from EP 0 718 099 that such Vacuum storage also as foil storage for storage of stamping foil web sections in a stamping rotary machine can be used. With relatively thin, sensitive stamping foil material is however to avoid of damage to the film material, possibly more constructive and / or control engineering effort required. If the train is inadequate, the very flutter can occur light, limp film material in the air flow of the sucked air come in, creating an embossed film damaged and / or the retraction force of the storage device can be affected uncontrollably.

The invention has for its object a storage device to create the disadvantages of the prior art Technology avoids. In particular, the storage device easy storage of thin, sensitive Stamping foil material, if necessary, in several parallel to each other allow running material webs.

To achieve this object, the invention proposes a storage device with the features of claim 1.

In a storage device according to the invention Claim 1 is a first pulling device on the feed side Pull the at least one material web towards the storage device and a separate, second pulling device on the discharge side for pulling the at least one material web direction Storage device provided. Between the related opposite to each other in the direction of web travel or interacting pulling devices on a large part of the length of the loop section and flat can gently attack this, there remains a free one Loop section that is essentially free of tensile forces is. It can be in relation to the total length of the loop section be very short and due to the inherent tension of the Material web material kept calm and flutter-free. Those adjacent to the free loop section Loop sections on which the traction devices can attack flatly by the pulling devices in one Distance from each other can be kept apart actively. Thereby can in particular be the risk of mutual contact this loop leg, for example, due to electrostatic Forces are avoided. This danger can Vacuum accumulators occur in which the entire length of the loop section is unguided or free and itself correspondingly the loop shape from the interaction between web tension forces and caused by negative pressure Suction forces results.

A preferred embodiment is characterized in that that the first traction device and / or the second traction device at least one movable in a feed direction, preferably in sections flat drive surface and Pressure means for pressing the material web flat against the Has drive surface. The tractive force of a traction device can thus over a large or elongated area gently transferred to the at least one material web become. By being close to each other arranged drive surfaces can the corresponding Loop legs are actively kept apart safely. It is preferably under the formation of sliding friction between the at least one material web and drive surface a slip drive formed. The development of sliding friction while avoiding static friction promotes a gentle, jerk-free and the material web material gentle conveying of at least one web of material and can be useful achieved that the speed of the drive surface in the feed direction is greater than that of the means of transport predetermined speed of the material web in this Direction. The first traction device preferably has and / or the second traction device has at least one rotating, each with a flat section of its outer surface the conveyor belt forming the drive surface.

To generate the necessary proof of the least a web of material on the drive surface is preferred provided that the pressure means a suction device for Suction of the at least one material web on the drive surface include that between material web and drive surface creates a negative pressure.

Alternatively or additionally, it is also possible, for example by a fan over an air flow which at least a material web from the side facing away from the drive surface to press on the drive surface. Such contactless Working pressure means are because of the achievable Protection of the at least one material web is preferred. A such air flow can in particular through a fan rail take place between the two train devices is arranged and transverse to the conveying direction of the at least a web of material runs in this area. At least a web of material is placed between the fan rail and the two Pulling devices passed through. The airflow emerges from the Fan rail in the direction of the two pulling devices out, whereby the at least one material web to the Pulling devices is pressed. The use of a Fan rail is particularly advantageous if several if necessary, different widths of material in one and the same storage device are temporarily stored should. It is not necessary to be close to the material web Provide adjacent guiding surfaces to the pressure difference between the drive surfaces facing away from the exhaust side of the fan rail and drive surfaces facing the side of the traction devices to maintain. This diminishes below the changeover times when new material webs from others Width to be passed through the memory. In The simplest design are the pulling devices fixed side walls to which the at least creates a material web and slides along it.

The pressure means can also work by touch Pressure elements, for example pressure brushes or the like. exhibit.

For particularly gentle and safe guidance the at least one material web in the storage device can be advantageous means for adjusting the tractive force for the first traction device and / or the second traction device be provided, for example depending on from the average transport speed in the main transport direction and / or the material web material the tensile forces get optimized. A control of the strength of the sliding friction between material web and drive surface can for example about the feed speed of the conveyor belt and / or about the suction power of the suction unit and / or the air flow of the Fan rail done.

A preferred embodiment is characterized in that that the drive surfaces of the first traction device and second traction device are facing each other and / or in run essentially parallel to each other. The drive surfaces can be used as movable walls in the feed direction act between which the loop section is approximately U-shaped runs with essentially straight legs. A den Distance between the loop legs determines the distance between the drive surfaces can suitably be chosen as large be that the free loop section in which the at least one material web is not in contact with any drive surface, held by the internal stress of the material itself and the material is only elastic without kinks is curved. On the other hand, the distance may be such be chosen small that changes in speed differences between supply and discharge area in one clear, possibly reliable by a sensor device detectable displacement of the free loop section within the storage device parallel to the feed direction noticeable.

The storage capacity can be designed so that for everyone Operating conditions there is sufficient storage space and neither overfilling nor complete emptying of the memory occurs. However, the degree of Storage fill to be monitored, if necessary, on the supply side and / or discharge side by appropriate control of the Railway transport material material speed changes to be able to make. In a preferred embodiment is a sensor device for detecting the storage filling provided the at least one distance sensor for detection one measured in particular parallel to the feed direction Distance between a free loop section and has a reference position. A distance sensor enables not just a simple record of the absolute filling level a storage device, but in particular also a easy recording of the dynamics of the memory filling, so a capture of the speed at which a memory is fills or empties. It is also possible to use one of the two Pulling devices or both pulling devices made of transparent Material - for example from a transparent Foil that is wrapped around two rolls and in a circle runs, with at least one of the two rollers driven and which is transparent in the area between the two roles is - to manufacture, and the location of at least one Capture material web via a camera that is on the Side of the transparent pulling device facing away from the material web is arranged. This is particularly advantageous if the position of several material webs in the same storage device should be monitored at the same time. The capture the memory filling dynamics enables a "predictive" Control of material supply and / or material removal for Storage device by not only when a permissible maximum filling levels corresponding control signals to a control unit, but also already when rapidly approaching an extreme state of memory filling.

A preferably non-contact sensor device is characterized in that it has at least one wave generator to generate electromagnetic and / or acoustic Has waves and that preferably at least one Receiving device for receiving through the free loop section reflected waves is provided. In particular can measure the distance using at least one Laser light source are made, in particular at least one photodiode can serve as a receiver. at a distance measurement via waves is particularly easy using the double effect also the speed of the Derive filling or emptying of the memory device and consider.

To achieve higher productivity, it is often desirable to in a facility using the material web material to process several material webs in parallel. A corresponding Storage device can preferably be used for storage several parallel, preferably independently movable material webs can be formed. While at conventional vacuum storage for this purpose between the individual Material webs partition walls are provided at suitable intervals must be to avoid safe suction to ensure the intake of secondary air, this is at storage devices according to the invention not required, because in particular a pulling device with slip drive several, possibly with different speeds can move moving material webs simultaneously, whereby possibly the speed differences between a drive surface and the web of material drawn from web to web differ.

Although it is possible to have a separate one for each material web To provide a sensor device for detecting the storage filling, it is particularly advantageous if the sensor device for sequential acquisition of the storage fill with at least two parallel to each other and preferably independently movable material webs between the Material web areas is movable. This not only at memories according to the invention, but also in conventional Storage devices, for example suction air stores very much advantageous measure saves on the part of the used Hardware, i.e. the sensors, costs and design effort, since a single sensor may be sufficient to detect one Monitor a variety of material webs. A sensor is expediently signal-transmitting with a control and evaluation unit connected over which the material web speed can be controlled on the supply side and / or discharge side. at several material webs monitored by a sensor the assignment of the degree of filling measurements, in particular the distance measurements, inexpensive within the control device be made by appropriate software.

Storage devices of the type mentioned can with all Facilities are used where storage of sections of continuous material webs required is, for example in printing machines, packaging machines, Embossing machines or the like. Since both on the import side and material on the discharge side with suitable tensile force into the Storage device can be retracted even complicated speed ratios between Simply compensate the supply and discharge side at any time. So can continuously feed material, for example supplied and intermittent or alternating on the discharge side Speed can be dissipated. It is also possible, a discontinuous material supply to a discontinuous or adapt continuous material removal.

With particularly great advantages can Storage devices for embossing devices, in particular Hot stamping devices are used. Such Embossing device has an embossing unit, in which between one Embossing cylinder and a counter pressure element, in particular one Impression cylinder, an embossing gap is formed. Farther is a transport device for transporting an embossing foil web from a film supply through the embossing gap to one Foil collecting device provided, the transport device Has film acceleration means that such are designed so that the embossing film web at least at the same speed as during an embossing interval a material layer to be embossed through the embossing gap emotional. This is necessary so that the embossed product, for example discrete embossing units in series like Pictures or texts, or a part of one to be stamped Color layer, undistorted or not smeared on the one to be embossed Material layer can be transferred and thus the Stamping foil web does not tear during the stamping interval. A Embossing device according to the invention is characterized in that that between the film supply and the film accelerators and / or between the film accelerators and the film collecting device at least one storage device the type described is arranged.

For embossing foil webs with discrete embossing units, a the best possible register accuracy, i.e. an exact position the stamping unit to the intended stamping location. at Embossing foils with layers of color, on the other hand, are aimed at minimizing from rejects with unused paint layer areas the smallest possible distance behind, still too defining color layer areas from previous ones, already areas of ink layer removed by embossing. To material to save, it is sought that one behind the other embossing color layer areas or embossing units on the Embossing foil web lie closer together than one behind the other Horizontal embossing locations on the material layer. It does it required that the stamping foil web be outside the stamping interval slower than the one moving normally Material position is performed before the embossing interval on the Material layer speed is accelerated and then is braked again and possibly also withdrawn. These speed changes are caused by the film acceleration means causes, under film acceleration both an increase in speed and a decrease in speed, as well as a reversal of direction Movement of the embossing foil web is understood. At a the film acceleration means are accordingly preferred to produce an uneven Movement of the material web is formed, preferably for Generation of a forward / backward movement in which the Material web at times in one of the main transport directions opposite reverse direction is moved. Do here the advantages of memory devices according to the invention particularly noticeable because of the possibility of bilateral, independent feeding of web material into the film storage as well as the possibility given by the hatching, Material against the feed direction is essentially free of distortion pulling out of the storage device, too Material web movements against the main transport direction can be easily accommodated.

Especially when the at least one moves backwards Material web can be on the feed side of the film accelerator memory fill problems arise when material of film stock is continuously replenished. At a preferred embodiment is therefore provided that the Foil stock, which is preferably an unwind storage roll for the embossing foil web can comprise, with regard to the delivery rate for Stamping foil is controllable. The control can in particular Dependence of the degree of filling and / or the filling speed the storage device downstream of the film supply take place, these control variables advantageously via the described sensor device can be detected.

These and other features go beyond the claims also from the description and the drawing, wherein the individual features individually or separately several in the form of sub-combinations in one embodiment of the invention and in other fields could be.

Fig. 1

eine schematische Seitenansicht einer Ausführungsform einer mit erfindungsgemäßen Speichereinrichtungen ausgestatteten Präge-Rotationsmaschine,

Fig. 2

eine schematische Darstellung eines Querschnitts durch eine erfindungsgemäße Speichereinrichtung und

Fig. 3

eine schematische Schnittdarstellung einer erfindungsgemäßen Speichereinrichtung mit einer Kamera zur Erfassung der Lage von Speicherbahnen.

An embodiment of the invention is shown in the drawing and is explained in more detail below. It shows:

Fig. 1

2 shows a schematic side view of an embodiment of an embossing rotary machine equipped with storage devices according to the invention,

Fig. 2

a schematic representation of a cross section through a storage device according to the invention and

Fig. 3

is a schematic sectional view of a memory device according to the invention with a camera for detecting the position of memory tracks.

1 schematically shows a hot stamping rotary machine 1 shown, for example for minting successive Sheets or a sheet of paper, cardboard or plastic can serve with embossed material in a transfer layer there is an embossing foil web. The rotary machine has one Embossing unit 2 with a horizontal embossing cylinder 3 and one about the same size, underlying impression cylinder 4, between which an embossing gap 5 is formed. The embossing cylinder 3 has at least one heatable along its circumference Embossing die 6, which is in the position shown during a Minting interval on one with uniform speed through the embossing gap material layer 7 one of the on the embossing foil web 8 existing embossing units on the Layer of material. The embossing foil web 8 has one Embossing cylinder 3 facing back 9 and a sensitive, a layer of a thermally activatable hot glue having front side 10. Fig. 1 shows the device during an embossing interval during which the material layer 7 and the embossing foil web 8 in the area of the embossing gap 5 have the same direction of movement 11 and with the same speed run through the embossing gap at a speed that the Peripheral speed of the counter-rotating cylinders 3, 4 corresponds.

The material web of the as yet unused stamping foil is in a film supply 15 in the form of an unwind storage roll before, by a not shown, with respect to its speed controllable motor is rotated in other versions but can also be passive or not driven. from Foil stock makes the embossing foil loop-shaped through a Foil feed storage device 16 explained later a film accelerator 17 performed both the speed as well as the direction of the foil movement controls in the embossing gap 5. In the main transport direction 11 behind the film acceleration device is a film removal storage device 19 arranged through which the embossing foil web is loop-shaped to form a foil collecting device for the used stamping foil web Winding storage roll 20 is pulled by a Electric motor not shown in the pulling direction with a uniform Rotational speed is driven. Through the one above the other horizontal storage rolls 15, 15 'and 20, 20' indicated that the hot stamping rotary machine 1 for processing several embossed foil tracks in parallel whose film transport can be controlled separately.

The structure of the film acceleration device 17 is similar to that of FIG foil acceleration device described in EP 0 718 099. The film accelerator has an embossing gap 5 in the transport direction 18 downstream traction device 22 with a Electric motor 23 driven at a uniform speed, revolving suction belt 24, the embossing foil web 8 facing top moves in the transport direction 18. in the Continuous perforations are provided on the conveyor belt 24, which are dimensioned and arranged so that they are the embossing foil webs lying against the flat contact surface are covered in groups depending on their width. All Embossed foil webs run in parallel run over the same Suction belt. The traction device 22 preferably operates in the Area of sliding friction between the suction tape and the embossing foil web, which is achieved in that the suction belt 24 in Transport direction 18 moves faster than the embossing film web. The traction device thus creates a permanent train on the embossing foil path in the direction of 18, but also allows a movement of the embossing foil web against direction 18.

The foil feed is connected upstream of the embossing gap 5 controlling film feeder 28 arranged. One regarding Direction and speed of programmable drive motor 29 drives a correspondingly in rotational speed and / or direction of rotation controllable control roller 30 on which the embossing foil web 8 by means of upstream or downstream Deflection rollers 31, 32 is guided so that the control roller about on one half of its circumference from the embossing foil web is entwined. The one in rolling contact with the stamping foil web standing control roller is designed as a suction roller, which in the looped area has effective suction openings which prevent the embossing film from slipping while building up static friction is sucked in. It is advantageous to have a firm, more suitable and in particular for driving the embossing foil web against the tractive force of the traction device more sufficient Adhesive contact to the control roller made without the sensitive front 10 is touched.

The film acceleration device 17 in particular a very advantageous for reasons of film material savings Forward / reverse operation of the embossing foil web allows. As mentioned, the embossing foil web is like this accelerates to the same speed during the embossing interval with the material web 7 through the embossing gap running. After the embossing interval, the material web is through Braking of the control roller 30 braked and by reversing direction the control roller 30 a bit through the embossing gap withdrawn to provide sufficient "run-in distance" for the Acceleration of the next embossing unit to that during the Throughput required to create the embossing gap. In the area of the film accelerator 17 occur both fast and slow Path movements in the direction of transport 18, as well as fast and slow material web movements against this main transport direction on.

In contrast, the material supply from the stock 15 and the Material removal on the take-up reel 20 as a rule deviating, possibly continuous web speed. The resulting path speed differences between Stock 15 and accelerator 17 or accelerator 17 and collecting device 20 are by the Storage devices 16 and 19 compensated, which act as a buffer between film supply 15 and film acceleration device 17 or film acceleration device 17 and film collecting device 20 act.

The structure of a storage device is shown using the example of Feed storage device 16 explained on the feed side by the unwinding speed of the storage roll 15 given feed path speed prevails while on their discharge side in the amount and direction in time with the Embossing intervals varying web speed in the film acceleration area 17 prevails. The storage device 16 has on its side facing the film supply 15 first traction device 35 in the form of an elongated suction belt and on the film acceleration device 17 facing discharge side a second traction device 36, the is also formed by an elongated suction belt. The two suction belts 35, 36 are identical in construction, with their longitudinal axes parallel to each other in mirror image a dashed line indicated 37 and are perpendicular to the center plane.

Each of the traction devices has one around two deflection rollers circumferential, perforated conveyor belt 38 and 39, respectively Conveyor belts by a common motor 40 such are driven in opposite directions that their each other facing, flat drive surfaces 41, 42 in one of the lower feed opening upward feed direction 43 (arrows) can be moved at the same speed. Are between the straight sections of the conveyor belts each connected to a common suction fan 44 Vacuum boxes 45, 46 arranged through the air through the perforations provided in the conveyor belts can be. The width of the conveyor belts 38, 39 corresponds a multiple of a film web width, so that several with small distance parallel to each other through the storage device guided embossing foil tracks together in the store can be drawn in.

A U-shaped accommodated in a storage device Loop section 47 has two parallel to each other straight loop leg 48, which by the suction belts 35, 36 securely guided along their entire length and at a distance to each other by pointing towards 43 moving drive surfaces are pulled, as well as one in Usually short compared to the loop legs, curved free loop section 49 which is not in Is in contact with the suction tapes, but accordingly the supply and discharge-side speed ratios parallel to direction 43 in the area between the positions of maximum and minimum indicated by dashed lines Storage fill can move back and forth.

On the opposite end of the feed opening is in Area of the central plane 37 a sensor device 50 for Detection of the memory fill arranged. The schematic Sensor device 50 shown has a sensor head 51, which in the space between the traction devices 35, 36 directed is and on a cross to the parallel embossing foil webs rail 52 perpendicular to the plane of the paper is movable that the sensor head 51 in succession at the the respective fill state next to each other detected. The sensor head has one on the center of the U-shaped curved free loop section 49 directed Laser light source and at least one photocell that the in this area reflected from the film web back 9 Light captured. An assigned evaluation device is determined from this the longitudinal distance between the free loop section and the sensor head serving as a reference point. In particular if the distance measurement over a suitable time interval is carried out, for example, in the Sensor head briefly above the film web to be measured is stopped, is from the temporal development of the Distance also the existing for the respective embossing foil web Filling or emptying speed of the memory derivable. The speed is also from the fill levels temporally defined successive path-related individual measurements derivable. The sensor head can do this continuously be moved.

The film removal storage device 19 is constructed identically, their pulling devices 55, 56 over the same Motor 40 at the same speed as the traction devices 35, 36 are driven and assigned to the suction belts Vacuum boxes connected to the common suction fan 44 are. In contrast to the storage device on the supply side prevails here on the feed side 55 by the Foil acceleration device 17 predetermined non-uniform Belt feed with forward / backward movement while on the Discharge side 56 a uniform discharge to the take-up storage roll 20 takes place.

2 shows a section in a schematic representation by a storage device 60 which is suitable as Foil feed storage device 16 or as a film removal storage device 19 to be used. The storage device 60 is formed from the two traction devices 61 and 62 and the fan rail 70. The at least one material web 65 is on the startup page 66 of the memory device 60 fed and leaves this on the discharge side 67. Each the two pulling devices 61, 62 consist of a pair Casters 64, at least one of which is driven, and a conveyor belt 63. The conveyor belt 63 runs around the two rollers 64 of the traction device around. This corresponds to the running direction of the conveyor belt 63 of the upstream side Traction device 61 of the conveying direction of the material web, during the running direction of the traction device on the outlet side 62 runs counter to the conveying direction of the material web 65. Due to the fact that a relative speed between material web 65 and the conveyor belts 63 of the Traction devices 61, 62 can exist, the nature of the conveyor belt 63 be designed so that damage the material web 65 due to this relative movement not happened. Between the rollers 64, the upstream or on the outlet side on the pulling device 61 or 62 are located, a fan rail 70 is arranged. The fan rail 70 extends in width across the width of the Conveyor belts 63 and thus determines the width that the may have at least one material web 65 to pass through the To be conveyable through storage device 60. The Fan rail 70 has air outlet openings over its entire width 72, from which an air stream emerges which the material web to the conveyor belts 63 of the pulling devices 61, 62 presses. Due to the air flow 71 Material web 65 pressed against the conveyor belts 63 that the material web 65 is moved into the storage device is being exercised, with a steady pull resulting from Airflow 71 flow velocity, movement velocity of conveyor belts 63 and friction between Conveyor belt 63 and material web 65 results. By suitable Material selection of the conveyor belts 63 and by coordination the rotational speed of the conveyor belts 63 in the Traction devices 61, 62 and the flow rate 71 of the air flow makes it possible to damage the material web without damage to lead in the area of the storage device 60. Different material web speeds can be used balanced between start side 66 and outlet side 67 become. It is not necessary that the rotational speed the conveyor belts 63 of the traction devices 61, 62 correspond to each other. Rather, it can be cheap Rotational speed of the conveyor belt 63 of the traction device 61 on the starting side 66, if possible, to the speed to adapt the material web 65 on the start-up side 66.

To the relative speed between conveyor belt 63 and Material web 65 at the traction device 62 on the outlet side To keep 67 as low as possible, the speed of revolution must be kept of the conveyor belt 63 of the traction device 62 likewise keep low. The slower this speed is, the less more the material web 65 through the air flow 71 in Direction towards the gap between the train devices 61 and 62 are acted out. The strength of the airflow 71 in turn is due to the material properties of the material web 65 limited. The width of at least play here one to be conveyed through the storage device 60 Material web is just as important as the inherent rigidity of the Material web 65. Therefore, in the coordination of these factors a suitable compromise in relation to the specific Find conditions.

The air outlet openings 72 of the fan rail 70 can be in be formed in different ways. It can happen for example around air outlet holes or around air outlet slots act. The air outlet openings 72 must be but be designed so that in the area between the traction devices 61 and 62 as uniform as possible, laminar air flow results. Furthermore, the air flow must not only on the space between the train devices 61, 62 aligned, but also on the conveyor belts of the pulling devices must be executed to an adequate extent Contact pressure for the material web 65 on the conveyor belts 63 to reach.

On the inlet or outlet side facing away from the material web Side of the pulling devices 61, 62 is between them Detection device 69 is provided, which is the distance to the between the traction devices 61, 62 free loop section 68 of the material web 65 detected. Become multiple webs of material 65 simultaneously in the storage device 60 stored, the detection device 69 is preferred Form so that they are the distance to the free loop sections 68 each web of material either simultaneously or cyclically in succession at a sufficient speed detected. This may be necessary in the detection device 69 to provide several sensors for distance measurement.

3 shows a further exemplary embodiment of a Storage device 60. This storage device 60 also essentially consists of two pulling devices 61 and 62 and a fan rail 70 is formed. Unlike that 2 has the pulling device 62 on the outlet side 67 of the at least one material web 65 additionally a suction box 73. The at least one Material web 65 is the storage device 60 on the Start page 66 fed. Through the air flow 71, which of the Blower rail 70 is generated, the web of material to the The conveyor belt 76 of the pulling device 61 is pressed. The The conveyor belt 76 of the pulling device 61 moves as well the conveyor belt 63 of the traction device 62 parallel to Air flow direction. This will at least moving a material web 65 with the conveyor belt 76 so far, until the material web 65 due to the speed the material web on the discharge side 67 not from the storage device 60 is pulled out. To improve Guiding the material web 65 on the conveyor belt 63 Traction device 62 on the outlet side 67 of the material web 65 can be reached on the material web 65 facing away A suction box 73 is arranged on the side of the pulling device 62. Air is permeable to air through the suction box 73 trained conveyor belt 63 sucked through, which the Pressure difference between the air pressure in the area of the air flow 71 and the side facing away from the material web Conveyor belt 63 is enlarged. The enlargement of the Pressure difference corresponds to an increase in the contact pressure of the Material web 65 to the conveyor belt 63 of the traction device 62. This measure may also contribute to the Relative movement between the conveyor belt 63 of the traction device 62 and to reduce the at least one material web 65. A relative speed between the conveyor belt 63 and the at least one material web 65 consists alone if only because the direction of movement of the conveyor belt 63 opposite to the direction of movement of the material web 65 is directed along the conveyor belt 63.

In order to load the material web as evenly as possible To reach 65 through the airflow 71, it can be advantageous be the blower rail 70 at several locations blowing air supply. The fan rail 70 can also be in a number divided by segments, each segment using a can have their own air supply, so that the air flow 71 of the through the air outlet openings 72 of the fan rail in Direction toward web 65 exits at everyone Segment can be another. This can then be the case, for example be advantageous if there are several in the storage device 60 Material webs 65 of different characteristics are temporarily stored become.

On the side of the traction device facing away from the material web 65 61 is as a detection device 69 for the free Loop section 68 of the material web 65 a camera 75 arranged. So that the camera 75 the position of the free loop section between the two pulling devices 61 and 62 can detect, the conveyor belt 76 is transparent educated. The camera has to depend on your Observation opening angle 77 may be arranged so that it the position of the free loop section 68 of the at least a material web 65 between the rollers 64 of the conveyor belt 63 or the transparent conveyor belt 76 can capture. The camera can also extend in the direction of extension the fan rail 70 has such an opening angle or one have such a distance from the transparent conveyor belt 76, that the entire width in the at least one web of material 65 can be performed. As a result, the camera is in the Position, at the same time the position of the free loop sections 68 of several material webs 65 to be detected. Over a suitable, not shown image evaluation device can then the position as well as the change in position of the free Loop sections 68 are evaluated. The camera 75 is thus an example of a detection device 69 that is able to simultaneously position several material webs 65 in the memory device 60.

The function of the system shown in Fig. 1, in particular of the storage facilities each equipped with a double suction belt 16, 19 is initially exemplified below for the Case explains that the web delivery speed from the film supply 15 essentially the web take-up speed of the Collection device 20 corresponds and substantially uniform is, while the film accelerating means 17 the Forwards / backwards movement of the embossing foil web described above with the film acceleration phases. The speed the conveyor belts in the feed direction is appropriate set so that both the import side and the discharge side the drive surface of a suction belt opposite the film has an excess speed so that it does not become Formation of static friction between embossing foil web and Conveyor belt comes, but in the sliding friction area Slip is worked. This promotes a film-friendly Gentle, jerk-free pulling of the pulling devices on the Stamping foil web in the feed direction. In the phases in which the feed-side path speed in the case of a store exceeds on the discharge side, the store will fill, by the free loop section in the direction of the assigned Sensor device moves upwards. During this hike remains essentially due to the internal stress of the Foil sheet and the distance of the suction tapes predetermined shape the free loop section essentially unchanged, while the parallel extend the straight leg of the loop section. there the straight legs are independent of the total length the loop over its entire length through the suction belts held and thus actively kept apart at a distance, the distance between the drive surfaces facing each other equivalent. In contrast to conventional vacuum accumulators So the loop section over the substantial part of its length, with the exception of the free Loop section, guided and held securely so that especially touching the loop legs, for example due to electrostatic attraction, reliable is avoided. The non-guided, free loop section on the other hand stands calmly and flutter-free between the Suction belts and can be used as a well-detectable reference surface for the distance measurement using the one aimed at him Serve sensor device. The positionally reliable web guide can can be guaranteed without special sealing measures, such as they are required for vacuum accumulators. In particular is also a change to foil webs of other widths without Effort possible because there are no side walls that limit the path must be provided.

For systems with a uniform supply speed on the supply side and / or uniform collection-side discharge speed is the storage capacity of the film storage to determine the total length of feed of the store that it is not for memory overcrowding or for complete Emptying of the memory can come. The storage dimension can be reduced by filling and / or filling or emptying speed of a memory by means of the Sensor device 50 monitors and, for example, the rolling speed the unwind storage roll 15 depending is controlled by filling level and / or filling speed. On Distance sensor is particularly advantageous for this, because not only the absolute levels, given by the (vertical) Position of the free loop section, detected can be, but by observing the temporal Course of the distance in particular also filling and emptying speeds. It can be used for a fast approach the degree of filling to a degree of filling extreme e.g. the feed rate be slowly reduced or increased early on instead of, as is conventional, only when the control process is reached of a filling degree extremum. This "foresighted" Control also enables e.g. the use of larger or heavier film supply rolls, which are due to inertia only let it accelerate slowly. Larger film stocks mean less machine downtime because of a roll change must be carried out less frequently. An in Distance sensor acting in longitudinal direction is opposite conventional position sensors acting in the transverse storage direction also advantageous in that a single sensor is sufficient to detect both fill level maxima and fill level minima.

Claims (18)

1. Storage device (16, 19) for receiving a loop section of at least one moving, flexible material web (8), particularly a stamping film web, between a feed area upstream of the storage device, in which the material web is moved at a feed web speed, and a downstream discharge area, in which the material web (8) is moved at a discharge web speed at least periodically differing from the feed web speed, wherein the storage device (16, 19, 60) has on the feed side a first pulling device (35, 55) for drawing the material web into the storage device and on the discharge side a separate, second pulling device (36, 56) for pulling the material web into the storage device.
2. Storage device according to claim 1, wherein the first pulling device (35, 55) and/or the second pulling device (36, 56) has at least one preferably sectionwise, planar driving surface (41, 42) movable in a pulling-in direction (43) and pressure means (44, 45, 46) for the flat pressing of the material web onto the driving surface, a speed of the driving surface in the drawing-in direction preferably being higher than the speed of the engaging material web (8) in the drawing-in direction.
3. Storage device according to claim 1 or 2, wherein the first pulling device (35, 55) and/or the second pulling device (36,56) has at least one circumferential conveyor belt (38, 39) in each case forming the driving surface (41, 42) with a planar portion of its outer surface.
4. Storage device according to one of the claims 2 or 3, wherein the pressure means comprise at least one suction device (44, 45, 46) for sucking the material web (8) onto the driving surface (41, 42).
5. Storage device according to one of the preceding claims, wherein a fan device (70) is disposed between the first and second pulling devices, the fan device (70) having at least one air outlet (72) for an air flow (71) for pressing the at least one material web (65) onto the pulling devices (35, 55, 61; 36, 56, 62).
6. Storage device according to claim 5, wherein the air flow (71) is a laminar flow.
7. Storage device according to one of the preceding claims, wherein the first pulling device (35, 36) and the second pulling device (55, 56) have driving surfaces (41, 42) which face one another and/or run substantially parallel to one another.
8. Storage device according to one of the preceding claims, wherein means are provided for adjusting the tensile force brought about on the material web by the first pulling device and/or second pulling device and preferably the suction intensity of a suction device and/or the movement speed of a driving surface is controllable.
9. Storage device according to the preamble of claim 1, particularly according to one of the preceding claims, wherein for the detection of the store filing a sensor means (50) is provided, which has at least one proximity sensor for detecting a spacing between a free loop partial section (49, 68) of the loop section and a reference position.
10. Storage device according to claim 9, wherein the sensor means (50) is constructed for detecting a speed change of the store filling.
11. Storage device according to claim 9 or 10, wherein the sensor means has at least one transmitter (51) directable onto a free loop partial section (49) for generating electromagnetic and/or sound waves and preferably at least one receiver for receiving waves reflected by the free loop partial section (49).
12. Storage device according to claim 11, wherein the transmitter (51) has at least one laser light source and/or the receiver at least one photodiode.
13. Storage device according to claim 9, wherein the sensor means (50, 69) is constituted by a camera (75).
14. Storage device according to claim 13, wherein the conveyor belt (76) of the pulling device (61) is transparent and the camera (75) is disposed on the side of the pulling device (61) facing away from the at least one material web (65).
15. Storage device according to one of the preceding claims, wherein it is constructed for storing several parallel, preferably independently moveable material webs and wherein the sensor means (50) has at least one sensor, which for the time-succeeding detection of the store filing in the case of at least two parallel-moveable material webs, is movable between the material web areas.
16. Stamping device, particularly hot stamping device, with a stamping press (2), in which a stamping gap (5) is formed between a stamping cylinder (3) and an impression element, particularly an impression cylinder (4), and with a conveying device for conveying a stamping film web from a film supply (15), through the stamping gap (5) to a film collecting device (20), the conveying device having film accelerating means (17) constructed in such a way that at least during a stamping interval is moved at the same speed as a material web to be stamped through said stamping gap, wherein between the film supply (15) and the film accelerating means (17) and/or between the film accelerating means (17) and the film collecting device (20) is provided at least one storage device (16, 19) according to one of the claims 1 to 11.
17. Stamping device according to claim 16, wherein the film accelerating means (17) are constructed for producing a non-uniform movement of the at least one material web (8), preferably for producing a forward/reverse movement, in which the material web is periodically moved in a reverse direction opposite to the main conveying direction (18).
18. Stamping device according to claim 16 or 17, wherein the film supply, which preferably incorporates a winding-off storage roll (15) for the stamping film web, is controllable with respect to the stamping film delivery rate, preferably as a function of the filling level and/or a speed change in the filling level of a storage device (16) downstream thereof.

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