JPS6237713Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bubble swaying device for a blown film forming apparatus.

In inflation film forming equipment, the molten bubble formed by extruding it into a tube shape from a die is usually cooled in a cooling device called an air ring, and then folded and rolled up. If the bubble is shaken by the air flow, the wall thickness may fluctuate or wrinkles may form, making it impossible to obtain a film of uniform quality. Therefore, several devices for holding bubbles to prevent them from shaking have been proposed or put into practice.

A camera diaphragm type camera in which curved blades are combined in the circumferential direction to form an almost circular opening in the center through which a bubble passes; a camera iris type in which a wooden frame is assembled in a parallel cross-shape; One example is the one shown in Publication No. 46-14947.

However, with aperture-type cameras, the air blown out from the air ring and rising is blocked by this, creating a vortex, which causes the bubble to shake.
There is a drawback that it is difficult to obtain a film with uniform quality and constant thickness, and even when wooden frames are assembled in a cross-shaped structure, this prevents air flow and creates vortices, and there are few contact points with bubbles, making it difficult to guide. However, it is difficult to carry out sufficiently, and furthermore,
As shown in No. 138666, arc-shaped arms are arranged vertically with different phases, so the arms contact the bubble from only one direction on the same circumference, making it easier for the bubble to deflect and providing a stable guiding effect. There is a problem in not being able to do this.

Moreover, neither of the above types can cope with changes in bubble size.

In this regard, a device that holds bubbles with a dogleg-shaped curved portion formed on a linear body, such as the one shown in Publication No. 14947/1982, is less likely to block the upward flow of cooling air and also prevent bubbles from being blocked. There are relatively many contact points on the same circumference, and the diameter of the part surrounded by the curved part can be adjusted according to the size of the bubble, but the diameter of the part surrounded by the curved part is To change the diameter, you must turn the nut to change the length of the bolt and change the inclination of the linear body.
It is difficult, time-consuming, and extremely troublesome to perform such work on each linear body so that the curved portions are aligned on the same circumference.

The present invention has been made in order to eliminate the drawbacks of the conventional devices described above, and the bending rod or bending rod is arranged in a rotational manner around an axis with the bending part or bending part facing inward, and the bending rod is arranged in a rotational manner with the bending part or bending part facing inward. The bubble is held at the periphery, and the upper and lower ends of the bending rod or bending rod are respectively supported, and an upper plate and a lower plate are provided through which the bubble passes, and at least one of them is supported so as to be movable up and down. The diameter of the small circumferential portion can be adjusted.

Here, the circumferential portion with the smallest diameter refers to the circumferential portion formed by the bent portion, the top of the bent portion, the bent rod, or a convex portion such as a roller protruding inward from the bent rod.

In addition, the axis refers to a straight line representing the center of a rotating body or the surface of a rotating body.

In the above device, the bending rods or bending rods include only those of the same shape and size, and the bending portions or the tops of the bending portions are all located on the same circumference, or two or more types of bending rods or bending rods having different shapes. There are cases in which the circumference formed by the bent part or the top of the bent part can be formed in two or more places in the vertical direction. It also includes two bending parts or bending parts arranged symmetrically in the vertical direction instead of the above.

To explain the following with reference to drawings, Figure 1 shows a bubble 2 formed by extruding a molten thermoplastic resin into a tube shape from a die 1, cooled by air jetted from an air ring 3, folded by a stabilizer plate 4, and folded by a pinch roll. 5 shows a schematic diagram of a blown film forming apparatus in which the film is wound up by a winding device (not shown) via a winding device (not shown), in which an anti-sway device A for holding the bubble 2 is provided above the frost line 6. Figure 2 shows an anti-sway device A constructed by rotating bending rods of the same shape and size around an axis. This shows a specific example of a configuration that can be adjusted according to the line position and bubble size.A fixing table 12 with a circular hole 11 of an appropriate size is provided with guide rods 13 arranged in parallel around the four sides. An upper movable plate 14 and a lower movable plate 15 are slidably provided on the guide rod. Each movable plate 14
A circular hole 16 concentric with the circular hole 11 is hollowed out in each of the pinions 15 and 15, and a rack 20 is provided which engages from both sides of a pinion 19 which is pivotally supported on the upper part of a column 17 fixed to the fixed base 12. The plate is the operating handle 21 of the pinion 19
When rotated clockwise in FIG. 2, they approach each other, and when rotated counterclockwise, they move apart.

The upper and lower movable plates move toward and away from each other around the pinion 19, and the bearing 23 that supports the pinion 19 is attached to the support 1 so that the center position can be adjusted.
It is attached so that its vertical position can be adjusted within a slit 24 formed in the vertical direction in 7. Between both movable plates, connecting rods 29 in which an upper rod 26 and a lower rod 27 are bendably connected by a hinge 28 are arranged side by side in a cylindrical shape at appropriate intervals, and are preferably bent within a plane passing through the axis thereof. Both upper and lower ends are pivotably attached to the circumference of the circular hole so as to be bendable. When the pinion 19 is rotated by operating the handle 21 to bring the upper and lower movable plates closer together, each connecting rod 29 is bent toward the axis at the hinge portion. Contact with the bubble is made at the hinge portion, that is, at the circumference of the smallest diameter of the rotating surface formed by the bending rods arranged in a rotational manner around the axis, and the circumferential portion has both upper and lower rods 26 and 27 of the same length. If the mounting positions of the upper and lower connecting rods are respectively on the circumference of the same diameter, they will be at the center of the rotating surface. In this embodiment, by moving the upper and lower movable plates 14 and 15 up and down by operating the handle, it is possible to not only adjust the diameter of the circumferential portion according to the size of the bubble, but also adjust the fold diameter and thickness. By changing the mounting position of the bearing 23, it is possible to easily and quickly cope with the vertical movement of the frost line, which changes depending on the film size such as thickness, extrusion conditions, cooling conditions, and various other conditions.

In cases where two or more types of bending rods with different shapes are used, and two or more circumferential parts with the minimum diameter are formed in the vertical direction as contact areas with the bubble, the lengths of the upper and lower rods are different. When bent rods are used, and the bent rods are placed vertically symmetrically with the bent rods turned upside down every other time or at appropriate intervals, the contact points to the bubbles formed in two places in the vertical direction are on both the upper and lower movable plates. By moving up and down, they can be simultaneously moved in the radial direction by equal amounts, making it possible to make adjustments according to the size of the bubble. In addition, in the above device, the hinge part that comes into contact with the bubble is coated with resin, or a roller is attached to the bending rod at an appropriate position, preferably to the hinge part (see Figure 3) to reduce frictional resistance with the bubble. It is desirable to reduce the

Further, in the above-mentioned device, both the upper and lower movable plates move symmetrically up and down, but only one movable plate may be moved up and down. In this case, the position of the hinge is adjusted in the radial direction and the vertical direction as the movable plate moves up and down.

In this case, if the movable plate that moves up and down is supported by a fixed plate, the fixed stand 12 shown in FIG. 2 is not necessary. Furthermore, instead of connecting the upper and lower rods 26 and 27 with the hinge 28, they may be connected with a connecting rod made of a material such as a spring, flexible rubber, or resin.

FIG. 4 shows an example in which a flexible rod 31 made of a helical spring, metal, resin, etc. is used in place of the connecting rod 29 in FIG. It is bent by moving the plate 15 up and down,
The diameter of the circumferential portion with the smallest diameter or the circumferential portion is designed to change vertically. The bubble may be brought into direct contact with the smallest diameter part of the center of the flexible rod, but as shown in the figure, rollers 32 are provided at appropriate locations on the flexible rod, preferably at the center, to reduce friction with the bubble. It is better to do so.

As described above, the anti-sway device of the present invention is constructed by arranging bending rods or bending rods in a rotational manner around an axis, and is designed to hold the bubble at the circumferential portion of the smallest diameter. It is possible to provide many points of contact with the bubble on the same circumference, and at these points the pitch of the rod is smaller than the large diameter part, so the stability of the bubble is extremely good, and the air ejected from the air ring is The bubble passes through and rises, and the flow is not obstructed, so the bubble does not sway due to air turbulence.

In addition, at least one of the upper plate and the lower plate supporting the upper and lower ends of the bending rod or bending rod can be adjusted in the vertical direction, and by adjusting the vertical position, the above-mentioned minimum diameter for holding the bubble can be adjusted. can be easily and quickly changed to suit different sizes.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the blown film forming device, Fig. 2 is a front view of the anti-sway device according to the present invention, Fig. 3 is an enlarged view of the hinge section with rollers attached, and Fig. 4 is a flexible It is a front view of the anti-sway device using a rod. 12...Fixed base, 13...Upper movable part, 15...
... lower movable part, 19 ... pinion, 20 ... rack, 26 ... upper rod, 27 ... lower rod, 28 ... hinge, 29 ... continuous rod, 31 ... flexible rod, 32 ... roller.

Claims (1)

[Claims for Utility Model Registration] (1) Forming through holes 16 that are arranged with appropriate spacing in the vertical direction and are large enough to form a sufficient gap between them and the bubbles 2 passing through. A bending rod or bending rod is arranged in a rotational manner around an axis passing through the center of the circumference on the circumference around the through hole of the upper plate 14 and lower plate 15, with the bent part or bent part facing inward. In a bubble swaying device for an inflation film forming apparatus in which the upper and lower ends are respectively attached and the bubble is held at the circumferential portion of the smallest diameter of the bending rod or bending rod, at least one of the upper plate 14 and the lower plate 15 is attached. A bubble anti-shake device that is supported movably up and down so that the diameter of the circumferential portion can be adjusted. (2) The bubble swaying device in the inflation film forming apparatus according to claim 1, wherein each of the bending rods or bending rods are all of the same shape and size. (3) A registration request in which each bending rod or bending rod is made up of two or more types of bending rods or bending rods with different shapes, and the circumferential portion of the minimum diameter for holding the bubble is formed at two or more places in the vertical direction. range 1
A bubble shaking prevention device in the blown film forming apparatus described in 2. (4) The bubble swaying device in the inflation film forming apparatus according to claim 3, wherein the bending rod or bending rod is made up of two types of bending rods or bending rods arranged vertically symmetrically. (5) A bubble swaying device for a blown film forming apparatus according to claim 1, wherein the circumferential portion having the smallest diameter is a bent portion or the top of a bent portion. (6) The bubble sway prevention device in the blown film forming apparatus according to claim 1, which is a convex portion protruding inward from the circumferential bending rod or bending rod having the smallest diameter. (7) A bubble swaying device for a blown film forming apparatus according to claim 1, wherein the convex portion is a roller. (8) A bubble swaying device for a blown film forming apparatus according to claim 1, wherein the bending rod or bending rod is arranged on the same plane as the axis. (9) A bubble shaking prevention device for an inflation film forming apparatus according to claim 1, wherein the upper plate and the lower plate are integrally movable up and down.