Device and method for guiding a blown film

Abstract

The invention relates to a guiding device for guiding a blown film between a film blowing die and a take-off roller device, comprising at least two lateral guides located opposite one another for laterally guiding the blown film, wherein at least one lateral guide is provided with a first guide segment and a second guide segment, which are connected to one another in an articulated manner. At least one lever kinematics is provided, which is in drive connection with a drive device, and which is interconnected with the two guide segments such that when the drive device is actuated by way of the lever kinematics, the angles of attack (αa, αe) of the two guide segments to the conveyance direction (F) of the blown film can be varied.

Claims

1. Guidance device for guiding a blown film between a film blowing head and a take-off roller device, comprising at least two opposing lateral guidances for the lateral guidance of the blown film characterized in that, at least one lateral guidance comprises a first guidance segment and a second guidance segment, jointly connected to each other, wherein at least one lever kinematics is intended, which comprises a plurality of at least two levers and is in actuation connection with a single common drive device and with both guidance segments in a way, that during actuation the drive device angles of attack (α.sub.a, α.sub.e) of both guidance segments are variable via the lever kinematics towards the conveyance direction (F) of the blown film; wherein α.sub.a is a feeding angle between the first guidance segment and the film blowing head, and α.sub.e is a gradient angle between the second guidance segment and the conveyance direction.

2. Guidance device according to claim 1, characterized in that the drive device comprises at least one slide which is translatory movably mounted and with which the lever kinematics is in gear connection at at least one position.

3. Guidance device according to claim 1, characterized in that at least a guidance rail is intended, in which at least one guidance lever of the lever kinematics is translatory movably mounted.

4. Guidance device according to claim 3, characterized in that the guidance rail forms an angle smaller than 90° with the conveyance direction (F) of the blown film.

5. Guidance device according to claim 3, characterized in that at least one first guidance rail and at least one second guidance rail is intended, wherein in at least one first guidance rail a first guidance lever of the lever kinematics and in at least a second guidance rail a second guidance lever of the lever kinematics is translatory movably mounted.

6. Guidance device according to claim 1, characterized in that the lever kinematics comprises a first section lever for the connection with the first guidance segment and a second lever for the connection with a second guidance segment.

7. Guidance device according to claim 1, characterized in that the lever kinematics comprises at least a first kinematics portion, which is connected to the first guidance segment via the first section lever and at least a second kinematics portion, which is connected to the second guidance segment.

8. Guidance device according to claim 7, characterized in that at least one of the two kinematics portions is in drive connection with the drive device.

9. Guidance device according to claim 1, characterized in that the drive device comprises at least one revolving chain device, via which the drive device is in drive connection with at least one further lever kinematics.

10. Guidance device according to claim 9, characterized in that the chain guidance is connected with at least one slide via at least one bracket, the chain device is translatory movably mounted alongside a rail and with which the lever kinematics is in drive connection at at least one position.

11. Guidance device according to claim 1, characterized in that at least a frame is intended, in which the drive device and/or the lever kinematics and/or the lateral guidance is mounted.

12. Guidance device according to claim 1, characterized in that the drive device comprises at least one electric motor.

13. Guidance device according to claim 1, characterized in that both lateral guidances are identically formed and both comprise a lever kinematics which are in drive connection with the same drive device.

14. Guidance device according to claim 4, characterized in that at least one first guidance rail and at least one second guidance rail is intended, wherein in at least one first guidance rail a first guidance lever of the lever kinematics and in at least a second guidance rail a second guidance lever of the lever kinematics is translatory movably mounted.

15. Guidance device according to claim 7, characterized in that the at least a second kinematics portion is connected to the second guidance segment via the second section lever.

16. Guidance device according to claim 8, characterized in that at least one of the two kinematics portions is in drive connection with the drive device, via at least one of the first guidance lever and the second guidance lever.

17. Method for adjusting the angles of attack (α.sub.a, α.sub.e) of guidance segments of opposing lateral guidances of a guidance device, for guidance of a blown film between a blown film head and a take-off roller device characterized in that angles of attack (α.sub.a, α.sub.e) of at least two guidance segments are varied in conjunction by the drive of a common drive device via a drive connection with at least a lever kinematics, which comprises a plurality of at least two levers; wherein the lever kinematics is connected to the guidance segments in a way that during the drive of the drive device the angles of attack of both guidance segments are variable towards the conveyance direction of the blown film via the lever kinematics; and wherein α.sub.a is a feeding angle between the first guidance segment and the film blowing head, and α.sub.e is a gradient angle between the second guidance segment and the conveyance direction.

18. Method according to claim 17, characterized in that the guidance device comprises at least two opposing lateral guidances for the lateral guidance of the blown film characterized in that, at least one lateral guidance comprises a first guidance segment and a second guidance segment, jointly connected to each other, wherein at least one lever kinematics is intended, which comprises a plurality of at least two levers and is in actuation connection with a single common drive device and with both guidance segments in a way, that during actuation the drive device the angles of attack (α.sub.a, α.sub.e) of both guidance segments are variable via the lever kinematics towards the conveyance direction (F) of the blown film.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is described in detail by means of the enclosed figures. The used phrases “left”, “right”, “top” and “bottom” are related to the orientation of the figures with normally readable references. It is shown schematically:

(2) FIG. 1 a first embodiment of the guidance device according to the invention with a maximal working width,

(3) FIG. 2 another embodiment of a guidance device according to the invention with a medium working width, and

(4) FIG. 3 an embodiment of a guidance device according to the present invention with a minimum working width.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

(5) In all three FIGS. 1 to 3 a diverse adjustment of the particular lever kinematics 30 and accompanied a corresponding diverse formation of the angles of attack α.sub.k, α.sub.e, α.sub.a is shown. As further learned from the three figures, the cross section of the respective blown film 100 differs. Particularly a correlation exists between the cross section of the blown film 100, which is pretended by the release cross section of the film blowing head 300 (not shown), and the adjusted or required angles of attack α.sub.k, α.sub.e, α.sub.a.

(6) By means of FIG. 1 the operating mode of the present invention should be described in detail. In this embodiment a blown film 100 is produced by a not shown film blowing head 300. This comprises a mainly round diameter. The blown film 100 is moved alongside the conveyance direction F towards a take-off roller device 200. The take-off roller device comprises at least two take-off roller which counterrotate towards one another and convey the lodged double layer of the blown film 100. For the distance between the film blowing head 300 and the take-off roller device 200 the guidance device 10 according to the invention is intended.

(7) For a variation of the angles of attack α.sub.k, α.sub.e, α.sub.a of the guidance device 10 according to the invention a respective lateral guidance 20 on the left and on the right side of the blown film is intended. Both lateral guidances 20 are opposing and mainly identical, which means formed with a common adjustability of the drive device 50. According to this, at present only the adjustment of one of both lateral guidances 20 is described, wherein this description operates also for the other lateral device 20 in the same way

(8) Each lateral device 20 comprises two guidance segments 22a and 22b. These guidance segments 22a and 22b are each shaped in a frame-like way and comprise guidance rollers 24, which ensure a lateral guidance of the blown film 100 in a minimal friction manner. At first the blown film 100 is restricted regarding the diameter transverse towards the conveyance direction F and subsequently expanded during the level process towards the take-off roller device 200. Thereby a first feeding angle α.sub.e, an articulation with an articulation angle α.sub.k and a discharge angle α.sub.a result towards the take-off roller device 200.

(9) In order to adjust the previously described angles, a drive device 50 is intended. This comprises according to this embodiment a motor 51 in form of a linear drive 51. This linear drive 51 of the drive device 50 accesses to the slide 52a, which is translatory movably mounted in a rail 54a. With other words, the slide 52a can be automatically adjusted in a rail 54a rightwards and leftwards via a motor 51.

(10) At the slide 52a a guiding to the lever kinematics 30 is intended at two positions. On the left edge a guidance to the second kinematics portion 30b and at the right edge of the slide 52a a guidance to the first kinematics portion 30a is intended. Each of both kinematics portions 30a, 30b comprises each a guidance lever 32a and 32b. Further, both of these kinematics portions 30a and 30b comprise a section lever 34a and 34b, by which an operative connection or a linkage respectively to the respective guidance segment 22a and 22b is intended. Both guidance segments 22a and 22b are jointly connected with one another via a joint 26.

(11) If the slide 52 is rightwardly moved in its rail 54a via the motor 51, an automatically drive of both kinematics portions 30a and 30b via the respective junction at the slide 52a occurs. Thereby the respective guidance lever 32a and 32b is automatically moved rightwards. By the rightward movement of the guidance levers 32a and 32b the edges of the guidance levers 32a and 32b follow each a guidance rail 56a and 56b via a wheel bearing assembly. Thereby the first guidance lever 32a moves upwards in the first guidance rail 56a while the second guidance lever 32b follows downwards. Both guidance rails 56a and 56b are not perpendicularly towards the conveyance direction F, but comprise contrary or aligned pointed angles of attack in different directions towards the conveyance direction F.

(12) By the movement described in the subsequent paragraph of both guidance levers 32a and 32b a tilting movement is brought to each of both kinematics portions 30a and 30b. This tilting movement or lever movement is transferred to the particular guidance segment 22a and 22b via the respective kinematics portion 30a and 30b of the lever kinematics, particularly via the respective section lever 34a and 34b. The transfer occurs in a higher or lower engagement of both guidance segments 22a.

(13) Basically this adjustment is shown in FIGS. 2 and 3, although there are shown slide variations of the guidance device 10 according to the invention. Therefore, by a rightward movement of the slide 52a a decrease of the diameter of the blown film 100 or an adjustment to a smaller diameter of the blown film 100 is respectively rendered. At the same time the feeding angle α.sub.e and the output angle α.sub.a as well as the articulation angle α.sub.k is diminished. At the limit stop according to FIG. 3 a minimum formation of all angles of attack α.sub.e and α.sub.a of both guidance segments 22a and 22b is recognized. At the same time a minimum diameter of the blown film is achieved. Naturally a removement in the opposing direction is possible in order to provide with a maximum diameter of the blown film 100 a maximum feeding angle α.sub.e and a maximum output angle α.sub.a.

(14) All embodiments according to FIGS. 1 to 3 have in common, that both lateral guidances 20 are shaped in an identical manner. In order to enable that a single motor 51 can vary all guidance segments 22a and 22b according to both lateral guidances 20 concerning the angles of attack α.sub.e and α.sub.a according to the invention, regarding FIG. 2 a chain device 58 is intended. It is particularly formed as a tape, preferably made of plastic and proceeds at the left and right edge of a corresponding frame 60 about deflector rolls 61. Via brackets 59 or bracket devices, a translatory connection between the first slide 52a, as it is described regarding FIG. 1 and a second slide 52b occurs. The connection via the brackets 59 occurs once at the upper and the other time at the lower edge of the slide 52a or 52b, so that during the circulation of the chain device 58 a reversion of the movement direction of both slides towards another occurs. If the left slide 52a is moved rightwards via the motor 51 a movement of the second slide 52b occurs to the left via the connection of both brackets 59 and the cooperation with the chain device 58. Both slides 52a and 52b are either moving towards one another or away from one another. Via deflector rolls 61 a corresponding drive shaft is able to drive an identical formation also on the opposing side above the drawing layer of FIG. 2, as shown in FIG. 2. This leads to a duplication of the entire mechanical parts, so that a bilateral mounting of both lateral devices 20 and both lever kinematics 30 as well as a bilateral influence to the respective kinematics portions 30a and 30b occurs. Also with this embodiment a variation occurs in a manner which is described in detail regarding FIG. 1.

(15) The subsequent descriptions of the embodiment are describing the present invention exclusively in examples. Naturally individual features of the embodiments, as long as they are technically meaningful can be freely combined without leaving the scale of the present invention.

(16) TABLE-US-00001 References 10 Guidance device 20 Lateral guidance .sup. 22a First guidance segment .sup. 22b Second guidance segment 24 Guidance roller 26 Joint 30 Lever kinematics .sup. 30a First kinematics portion .sup. 30b Second kinematics portion .sup. 32a First guidance lever .sup. 32b Second guidance lever .sup. 34a First section lever .sup. 34b Second section lever 50 Drive device 51 Motor 52a, 52b Slide 54a, 54b Rail .sup. 56a First guidance rail .sup. 56b Second guidance rail 58 Chain device 59 Bracket 60 Frame 61 Deflector roll α.sub.k Angle of attack α.sub.e Angle of attack α.sub.a Angle of attack 100  Blown film 200  Take-off roller device 300  Film blowing head F Conveyance direction