Device at strip formed material
The present invention relates to an arrangement for an installation for splicing web-shaped products involving switching the product web that is so arranged as to be fed into a splicing installation of the kind in question from separate web magazines.
In the case of production machines that are operated continuously, it is necessary to be able to achieve splicing of the material webs that are used in the manufacture of intended materials, e.g. sanitary articles such as disposable nappies and sanitary towels and other strip-shaped manufactured products. A roller stand is utilized to a large extent in conjunction with this, where roll-based materials are used as a part of the products that are produced.
The material in supplied in rolls from the raw material supplier, and the purpose of utilizing a roller stand is to ensure that the material is unrolled and fed into the production machine. The production machine draws the material into the process, and the function of the roller stand is thus to discharge the right quantity of material per unit of time.
A common roller stand for use in sanitary item production machines can be equipped for the automatic in-feed of the material, and a roller stand of this kind can consist of three principal components, in addition to the stand itself, namely: • one or two spindles,
• splicing unit, and
• buffer magazine.
In most cases, each spindle is driven by its own motor. The buffer magazine ensures that material is "issued" whenever the production machine concerned requests it, and the function of the spindles is to ensure that the buffer magazine is filled to the right level. The buffer will usually be relatively small under normal operating conditions.
When the material on one spindle is about to run out, this is detected by a sensor, and a larger buffer of material is built up in the buffer magazine, which can be used while splicing from one roll to the next takes place. This means that the material is fed continuously from the stand, while the spindles are actually brought to a standstill and remain stationary for the period during which actual splicing takes place. The actual splicing between the "old" material and the new material very often takes place with the help of taping or welding by the application of heat. The old material is cut off inside the splicing unit in conjunction with splicing of the new material. The splicing operation itself takes only 1-2 seconds, and it is usual for a small amount of material to remain on the old roll after splicing has taken place. The sleeve formed by the material remaining on the old roll is removed by an operator, and a new roll is installed and prepared in such a way that the next splicing operation can proceed successfully. The above splicing method is known as "zero speed splicing". There are also other stands with other methods of splicing. The choice of method takes account of the type of material to be unrolled, the speed and the accuracy requirement for the tension of the web, etc. The size of the buffer magazine can vary, and
it may be installed both horizontally and vertically, but it may also have other constructional forms.
A standard roller stand will function very well for the majority of materials. This is especially true when the material is relatively thin and homogeneous and is supplied in single rolls.
Having regard for the fact that the material web arrives in the splicing unit from different directions, the actual material splice will have a different appearance. Fig. 2 illustrates the appearance of the splice in the two previously disclosed cases. Relatively narrow materials have since emerged, which are most easily handled when they are supplied in large rolls, so-called "spooled rolls". Such materials can exhibit relatively large material thickness, high material rigidity and may sometimes possess an adhesive glued surface. Material with an adhesive coating is generally used in the products in the form of short pieces and is accordingly fed into the machine at quite a low speed. When splicing such materials, there are circumstances in which it is wished for the splice to exhibit the same appearance regardless of the side of the splicing unit from which the material emerges. A standard splicing unit is also relatively expensive for the use of the materials described above, because it is relatively complicated mechanically and electrically and is intended for quite high material speeds (100-500 m/min) . Problems are consequently encountered with the use of previously disclosed roller stands for the splicing of such material webs.
A principal object of the present invention is to make arrangements such that the splice is situated on the same side of the material web regardless of whether the material web comes from one or other roll in a web magazine. This is made possible by means of an arrangement of the kind defined in Patent Claim 1.
The arrangement that is previously disclosed through US 5679207A comprises a splicing unit in which a pivotally mounted splicing arrangement is located next to the in-feed of the film that it is intended to splice. Film from different rolls can be fed into the aforementioned pivotable splicing arrangement. However, as can be clearly appreciated from Fig. 12 in the aforementioned patent, film is fed in from different spools, of which one spool is rotated through 180° in relation to the other spool, in order to get the sides of the films on common sides as they are unspooled. The out-feed of spliced film extends along a plane that is common to an in-feed plane for the film from the respective film roll. Deflection of the film with the previously disclosed arrangement is great for one of the spools, at almost 180°, and this is associated with a high risk of fracture of the fed material web in the case of sensitive materials.
Previously disclosed through EP 0 598 265 Al, for example, is an arrangement for the splicing of tapes, where cutting and splicing devices are caused to be displaced laterally between arriving material webs. All the web roll magazines are supported by a common bearer plate, which is displaced laterally across the direction of travel of the webs. This causes significant storage problems, and high forces are called for in order to move heavy rolls.
Other similar devices are shown in US 4,089,482A, US 5,514,237A, which produce splices on different sides of spliced webs, and in US 5,575,626A. This is also shown in the drawing in Fig. 2 of the present case.
The principal object of the present invention is thus, among other things, to solve the aforementioned problems so that the material web is protected as far as possible.
In accordance with the present invention, this is achieved in the manner defined in Patent Claim 1; see in particular the characterizing part of the Claim and the qualification, "..., and in that the plane of the web through the splicing unit lies essentially perpendicular to the axis of rotation of the swivel arm." This distinctive feature is not previously disclosed, either through the aforementioned US 5679207A or through US 2035682A, which shows a swivelling transfer unit for the supplied web between splicing and cutting devices permanently situated to either side of the web. This previously disclosed installation also runs with the web in a common plane respectively in conjunction with in-feed into and out-feed from the installation.
The invention is described below as a preferred illustrative embodiment, in conjunction with which reference is made to the accompanying drawings, in which:
Figs. 1 and 2 illustrate schematically parts of previously disclosed splicing installations for web-shaped materials that are cut and spliced while in motion; Figs. 3-4 illustrate the invention, where:
Fig. 3 shows a schematic view of the whole splicing unit with the roll magazine illustrated;
Fig. 4 shows the actual cutting and splicing unit in perspective in its operating position directly in line with a fed-in material web; and
Fig. 5 illustrates an alternative, where the material web has been deflected through 90° from the splicing unit .
An arrangement 1 for an installation 2, which is intended for splicing web-shaped materials involving switching the material web 3A, 3B that is so arranged as to be fed into the splicing installation 2 in question from separate rolls 4A, 4B of material next to a preferably common web magazine 5, comprises a splicing unit 6 that is capable of being supported fully or partially by a swivel arm 7. The aforementioned swivel arm 7 is so arranged as to be capable of being caused to swivel between two or more in-feed positions A,B..., to which the web 3A, 3B of material is so arranged as to be capable of being guided from an associated web magazine 5. The plane of the material web 3 through the splicing unit 6 thus lies essentially perpendicular to the axis of rotation 14 of the swivel arm.
A splicing installation 2 of this kind is simple and inexpensive to manufacture and is so arranged as to feed out the material web 3 with the splice situated on the same side of the material web regardless of whether the material web comes from one or the other roll 4A, 4B in the web magazine 5. The swivel arm 7 is preferably so arranged as to swivel along an essentially horizontal plane 8, and the free end 9 of the swivel arm is so
arranged as to swivel into position directly opposite a cutting device for the material web 3A, 3B in question. A buffer magazine 10, for example of a previously disclosed kind, is arranged along the path 11 of the material web after the swivel arm 7. The swivel arm 7 supports the splicing unit 6 fully or partially at the free end 9 of the arm, with the operating part 12 of the aforementioned unit, preferably capable of displacement in a vertical sense, so arranged as to operate when positioned at a separate and preferably raised level 13 from the swivel arm 7, and with a stop 50 being positioned so as to act preferably at a lower level 51.
As it leaves the swivel arm 7, the material web 3 passes through the axis of rotation 14 of the swivel arm, which in turn is so arranged as to pass between two rollers 15,16 situated close together and extending vertically.
The material web 3 is so arranged as to be diverted through essentially 90° from the swivel arm 7 with its plane 17 along the direction of travel 11 of the web, for example as illustrated in Fig. 4, and is so arranged as to run between pairs of interacting rollers 15, 16; 15A, 16A, which are arranged in pairs perpendicularly in relation to one another or are diverted around angled rollers 20, 21, for example, as shown in accordance with the illustrative embodiment in Fig. 5. The material webs 3A, 3B come from rollers 4A, 4B, of which the axes of rotation 18,19 are supported horizontally, and the aforementioned swivel arm 7 can be caused to swivel along an essentially horizontal plane 8 by means of a drive device which, although not illustrated or described in greater detail here, can be in the form of a pneumatic cylinder, for example. The function of the invention is described briefly below with reference to Figs. 3 and 4 and Fig. 5 respectively.
An outline drawing of the possible appearance of such a stand is shown in Fig. 3. The actual splicing unit is illustrated schematically in Fig. 4. The roller stand is executed with two in-feed stations, where material, for example from spooled rolls 4A, 4B, is fed in. The material web 3A, 3B passes through the new splicing unit and into the buffer magazine 10, which in this case is positioned above the splicing unit. The splicing unit 2 consists of a swivelling arm 7, which swings between two stations A and B.
When a material is about to run out on one roll, for example roll 4B, the buffer magazine 10 is built up and in-feeding is halted, at the same time as the knife 12 (which is mounted on the swivel arm 7, for example) cuts the connection to the old material 3B .
As soon as the material web has been cut, the swivel arm 7 is caused to swivel across, for example by a pneumatic cylinder, to station A, where a new material 3A already prepared with a splicing tape is lying. As soon as the swivel arm 7 is in position, in station A, the ends of the material webs are pressed together, for example by a pneumatic cylinder (not illustrated) , and the material web is then released. In this way, the tape now always ends up on the same side. The operator then removes the old material web at station B, installs a new roll and prepares for new splicing when the material 3A at the aforementioned station A runs out.
Feeding of the material can take place either by means of driven spindles or with feed rollers.
It is also possible for guide rollers and their position to be executed in such a way that the path from the splicing point, i.e. the cutting point, to a point on the feed-out side is executed so that the section remains constant regardless of the swivel angle/lateral displacement.
This can be achieved with the correct geometry of the guide rollers and the positioning of the swivel point, or with a simple mechanism which compensates for any lateral displacement. A characteristic of this kind may be important in the case of certain materials of the kind concerned in order to ensure that the material exhibits the same tension during the principal splicing movement.
Fig. 5 illustrates how the spliced material web 3 fed out from the swivel arm 7 is guided and diverted in a direction 53, which is rotated through 90° from the feed-out direction 52 by means of rollers 20, 21, which are arranged parallel with one another in pairs, but are arranged perpendicularly in pairs in relation to feed-our rollers 54, 55 arranged in pairs for the swivel arm 7.
The invention is naturally not restricted to the embodiments described above and illustrated in the accompanying drawings. Modifications are possible, in particular with regard to the nature, positioning and plane of movement of the various component parts, or by the use of equivalent technology, but without departing from the area of protection for the invention as defined in the Patent Claims.