Device for stretching film webs in machine direction with several rollers having a quick-change device for changing rollers and method for changing rollers in stretching systems by means of a quick-change device

Abstract

Device for stretching film webs in machine direction with several rollers, of which at least two are stretching rollers (5) which define a stretching gap over which the film web (1) is guided characterized in that the device has quick-change devices for changing rollers (12), wherein the quick-change device comprises two bearing units (15) for excluding a roller (12), wherein the bearing units (15) are arranged on both sides in the side plates (13) of the machine frame of the device, wherein the bearing units (15) can be moved outwards by means of linear guides (14) and the roller (12) can be released, and wherein the quick-change device has media passages for supplying the roller (12) with media.

Description

[0001] The invention relates to a device for stretching film webs in the machine direction with quick-change devices for rollers according to the preamble of claim 1 and a method therefor.

[0002] In film production, stretching machines are used to reduce the thickness of the film after it has been produced. Stretching is used for both tubular and cast film.

[0003] A stretching line typically consists of heating rollers to prepare the film for stretching, followed by stretching rollers between which the film is stretched. Stretching can be followed by annealing or tempering rollers, where the film undergoes a temperature treatment to influence its properties. Finally, the film is cooled using chill rollers. By stretching the film webs, not only are their geometric dimensions changed, but their properties, such as transparency or strength, can also be specifically influenced.

[0004] Stretching systems are operated inline in blown film lines or offline. Stretching of tubular film can be performed inline in blown film lines directly after the take-off roll pair or after the turner bar system following the take-off roll pair.

[0005] Due to contamination and wear, rollers in stretching lines need to be replaced. Removing rollers from stretching lines is very time-consuming and takes several hours, resulting in production downtime.

[0006] When using vacuum rollers in stretching systems, as described in DE 10 2020 000 334 A1, cleaning is important, as monomers can clog the openings of the vacuum roller. Cleaning these rollers is very time-consuming, and the vacuum rollers must be removed at regular intervals for this purpose. This requires interrupting production.

[0007] DE 83 13 265 U1 discloses a quick-change device for rollers in paper processing machines, among other things. The roller is held on both sides by bearing units that are arranged so that they can be moved in the direction of the roller axis, thus releasing the roller for removal.

[0008] EP 0 442 253 A2 discloses a film stretching system in modular design in which the modules are installed and removed individually.

[0009] US 4 552 007 A discloses an exchange of rolls in rolling stands in rolling mills and a device for exchanging the rolling stand rolls, the device having traveling gears.

[0010] DE 10 2019 124 253 describes an identification system for rolls in a calender.

[0011] It is therefore an object of the present invention to provide a device and a method which enables a rapid change of rolls in stretching systems.

[0012] The object is achieved by means of an inventive device according to claim 1 and an inventive method according to claim 10. Further design features of the inventive device and the inventive method are the subject of subclaims 2 to 9 and 11 and 12, respectively.

[0013] To replace rolls in stretching systems, they are provided with tapered roll necks on their end faces, which are arranged coaxially to the roll rotation axis.

[0014] The rolls are mounted on the roll necks in bearing units of the stretching system. The bearing units are designed with internal cones along their rotational axes, into which the rolls are mounted on the roll necks. The roll necks and bearing cones are detachably connected.

[0015] The bearing units are arranged on the right and left sides of the side plate of the stretching machine frame, and are movable in linear guides. The rollers are driven by geared motors located in the frame of the stretching machine.

[0016] To remove a roll, a support device, which is suspended in guides in the side plates of the stretching machine frame, is moved under the roll to be removed, and the roll is placed on it. The bearing units are then released from the roll journals and moved outward along the linear guide. This can be done using a spindle. The roll to be removed is picked up by the support device and guided outward from the MDO together with the roll. There, the roll can be picked up by a forklift.

[0017] Rollers that are frequently replaced in stretching systems are stretching rollers, especially vacuum rollers. These rollers are subjected to negative pressure or, for cleaning, to positive pressure. They can also be designed as heating or cooling rollers. In these cases, media feedthroughs are provided.

[0018] The media feedthroughs are located on the front of the rollers and extend to the outside via the bearing unit and the drive, terminating in a rotary union. Sealed plug-in connections with sealing rings, such as radial shaft seals or O-ring systems, are used for this purpose.

[0019] One side of the roller is supplied with water or another temperature control medium for cooling or heating, while the other side is supplied with air or gas so that a negative pressure or positive pressure can be set.

[0020] In a further embodiment of the invention, the quick-change device is combined with a gap adjustment for the stretching gap. For this purpose, the complete quick-change device, including the bearing unit and the corresponding roll, is adjustable via a linear guide in the side plate of the machine frame.

[0021] The quick-change device can be used for any roll in a stretching system. It is preferably used for rolls that require frequent changes. These include vacuum stretching rolls and rubber-type stretching rolls.

[0022] Stretching systems are understood here to mean all devices that can change the length of film. This is not limited to film stretching; it also includes stretching and drawing. Stretching systems can be operated inline in blown film lines or offline. They can be installed at various points within a blown film line, downstream of the turner haul-off or directly downstream of the pair of take-off rolls, and upstream of the turner bar system, if present.

[0023] Stretching systems can be equipped with a quick-change device and additional roller detection. These are based, for example, on barcode, QR code, or RFID code systems. The code records roller characteristics such as geometric dimensions, materials, and even rubber compounds and rubber hardness.

[0024] However, the roller detection can also be used in stretching systems without a quick-change device.

[0025] Embossing rollers can also be included in the stretching system. These emboss the film with an imprint. This can be a mark, a pattern, or a logo. The mark allows the film to be identified. Such an embossing roller can also be equipped with a roller detection system.

[0026] The procedure for changing rolls in stretching lines with quick-change devices comprises the following steps: - Loosen the connection between the roller and the bearing unit - The bearing units move outwards on linear guides in the side plate of the machine frame of the stretching system - Placing the roller on a receiving device - Removing the roller from the stretching system - Inserting a new roller - Moving the roller to its installation location - Moving the bearing units together in the linear guides - Connecting roller and bearing units

[0027] If media feedthroughs are provided to supply the rollers with media such as heating and / or cooling agents and gas for negative or positive pressure, the following additional steps are carried out: - Disconnecting media supplies - Disconnect the media supply before removing the roller and - Connecting the media supply - Turn on the media supply after installing the roller.

[0028] A quick-change device allows rolls in the stretching line to be changed in significantly shorter times, resulting in shorter production interruptions.

[0029] Further details, features and advantages of the subject matter of the invention emerge from the subclaims and from the following description of the associated drawings, in which a preferred embodiment of the invention is shown by way of example.

[0030] The drawing shows: Fig. 1 a view of the stretching system with quick-change device Fig. 2 a section of a quick-change device for rollers with media feedthrough

[0031] The Fig. Figure 1 shows a stretching system, also known as MDO, for changing the length of a film web in the machine direction. The film web (1) is fed into the stretching system from above via a guide roller (10). First, it is guided over a heating section (2) with heating rollers (3). The film web (1) is then fed to the stretching section (4) with the stretching rollers (5) and a stretching gap in between, and stretched. The stretching rollers (5) can have a smaller diameter than the heating rollers (3). The film web (1) is then fed to an annealing section (6) with annealing rollers (7) for tempering, followed by a cooling section (8) with cooling rollers (9). Finally, the film (1) leaves the MDO system and can, for example, be wound up in the downstream winder (not shown here). The film web is held on the various rollers by lay-on rollers (11).

[0032] Fig. 2 shows the quick-change device in detail.

[0033] The quick-change device is arranged on both sides of the side plate (13) of the machine frame of the stretching system.

[0034] It holds the roller (12) on both sides at its frontal, truncated cone-shaped roller journals in a rotatable and form-fitting manner in the bearing units (15).

[0035] The bearing units (15) have internal cones along their rotational axes to support the roller (12) at its roll neck. The connection is established via a driver.

[0036] The bearing unit (15) is radially surrounded by the drive bell (21) and is inserted in a linear guide (14), which accommodates the bearing unit (15) with drive bell (21) and the axially adjoining coupling (20) as well as gear motor 17 in a displaceable manner in the side plate of the stretching system.

[0037] The roller can be engaged and disengaged via the sliding unit (16) arranged on the bearing unit (15) by moving the bearing unit (15) in the linear guide (14) towards or away from the roller (12).

[0038] To remove the roller (12), a support device (not shown here) is moved underneath the roller (12). The roller (12) is then moved so that it rests on the support device. The roller (12) can then be disengaged by moving the bearing units (15) away from the roller. The roller (12) is then moved out of the stretching system on the support device.

[0039] Media feedthroughs are provided to supply the roller (12) with media for operation as a cooling, heating, or vacuum roller. The roller (12) has a feedthrough on the roller neck at the front end, into which a siphon tube (18), for example, for the suction unit, is arranged. This tube (18) is guided axially through the bearing unit (15), the coupling (20), and the gear motor (17), and ends in a rotary feedthrough (19). List of reference symbols 1 film strip 2 heating sections 3 heating rollers 4 stretching section 5 stretching rollers 6 Annealing section 7 annealing rollers 8 Cooling section 9 cooling rollers 10 guide rollers 11 lay-on rollers 12 rollers 13 Side plate of the machine frame 14 Linear guide 15 storage units 16 Sliding unit 17 Transmission and engine 18 Siphon pipe for media feedthrough 19 Rotary union 20 Clutch 21 Drive bell 22 Gap adjustment

Claims

[1] Device for stretching film webs in machine direction with several rollers, of which at least two are stretching rollers (5) which define a stretching gap over which the film web (1) is guided characterized by , that the device has quick-change devices for changing rollers (12), wherein the quick-change device comprises two bearing units (15) for excluding a roller (12), wherein the bearing units (15) are arranged on both sides in the side plates (13) of the machine frame of the device, wherein the bearing units (15) can be moved outwards by means of linear guides (14) and the roller (12) can be released, and wherein the quick-change device has media passages for supplying the roller (12) with media. [2] Device according to claim 1, characterized bythat a receiving device for the roller (12) is arranged below a roller (12) to be removed, onto which the roller can be placed and can be moved out of the device for stretching. [3] Device according to claim 1 and 2 characterized by that media passages for media for tempering, negative pressure or positive pressure operation of the rollers (12) are provided. [4] Device according to one of the preceding claims characterized by that the roller (12) is a stretching roller. [5] Device according to one of the preceding claims characterized by that the roller (12) is a stretching roller designed as a vacuum roller with media passages. [6] Device according to one of the preceding claims characterized by that the roller (12) is a rubber roller, a smooth chrome roller or an embossed roller. [7] Device according to one of the preceding claims characterized bythat the quick-change device can be combined with a gap adjustment of the stretching gap, whereby the complete quick-change device with bearing unit and roller can be adjusted via a linear guide in the side plate of the machine frame. [8] Device according to one of the preceding claims characterized by that the device has a roller recognition with coding systems, wherein the coding system has information on roller properties. [9] Device according to one of the preceding claims characterized by that the roller (12) is an embossing roller, which provides the film with a marking by means of which the film can be identified. [10] Method for changing rolls in stretching systems with quick-change device according to claims 1 to 9, the method comprising the following steps: - Loosen the connection between the roller and the bearing unit (15) - The bearing units (15) move outwards on linear guides (14) which are arranged in the side plates (13) of the machine frame of the stretching device - Placing the roller (12) on a receiving device - Removing the roller (12) from the stretching device - Inserting a new roller (12) - Moving the bearing units (15) together by means of linear guides (14) to accommodate the roller (12) - Connecting roller and bearing units. [11] Method according to claim 10, characterized by that in the case of a quick-change device with media feedthroughs, the media supply is switched off and disconnected before the roller is removed. [12] Method according to claim 10, characterized by that in the case of quick-change devices with media feedthroughs, the media supply is switched on together.

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