JP7810339B2 - Blown film molding device, sizing ring of blown film molding device, and movable member of sizing ring of blown film molding device - Google Patents

Description

The present invention relates to an inflation molding apparatus, a sizing ring for the inflation molding apparatus, and a movable member for the sizing ring for the inflation molding apparatus.

An inflation molding device extrudes molten resin from a die into a tube shape, then blows air into the inside of the tube to inflate it and form a thin film (see, for example, Patent Document 1). There are two types of inflation molding devices: an upward type that extrudes molten resin upward, and a downward type that extrudes molten resin downward.

The inflation molding device is equipped with a sizing ring. The sizing ring determines the outer diameter of the bubble, which is a tubular resin film. The sizing ring forms an insertion hole through which the bubble passes. A film of refrigerant, such as cooling water, is formed between the wall of the insertion hole and the bubble. The outer diameter of the bubble is smaller than the diameter of the insertion hole by the thickness of the refrigerant film.

Japanese Patent Application Laid-Open No. 2005-231266

Previously, when changing the outer diameter of the valve, it was necessary to change the diameter of the insertion hole and replace the sizing ring. Replacing the sizing ring was a complicated task and a significant workload. Replacement also took time, during which time resin film production was halted. Furthermore, molding had to be stopped to replace the sizing ring, resulting in resin loss when molding was restarted.

A sizing ring equipped with a variable hole diameter mechanism that changes the diameter of the insertion hole is considered. The variable hole diameter mechanism has multiple movable members that define the insertion hole and are arranged continuously around the circumference of the insertion hole. The multiple movable members can move in both directions, to reduce the hole diameter and to increase the hole diameter.

However, when multiple movable parts are moved in a direction that changes the hole diameter, gaps may occur between the sliding surfaces of adjacent movable parts. If a refrigerant such as cooling water leaks out through these gaps, the refrigerant film will not form uniformly between the wall surface of the insertion hole and the bubble, resulting in molding defects.

One aspect of the present invention provides technology that suppresses molding defects.

An inflation molding apparatus according to one aspect of the present invention includes a sizing ring that forms an insertion hole through which a bubble passes. The sizing ring includes a hole diameter changing mechanism that changes the hole diameter of the insertion hole. The hole diameter changing mechanism includes a plurality of movable members that define the insertion hole and are arranged continuously in the circumferential direction of the insertion hole. The movable members include separation limiting portions that limit the separation between adjacent movable members. The separation limiting portions limit the separation between the sliding surfaces of adjacent movable members.

According to one aspect of the present invention, by limiting the separation between the sliding surfaces of adjacent movable members using a separation limiting portion, it is possible to prevent gaps from forming between the sliding surfaces and reduce molding defects.

FIG. 1 is a diagram showing an inflation molding apparatus according to one embodiment. FIG. 2 is a cross-sectional view showing an example of the second cooling device of FIG. 3A and 3B are perspective views showing a sizing ring according to one embodiment, in which FIG. 3A is a perspective view showing a state in which the hole diameter is maximum, and FIG. 3B is a perspective view showing a state in which the hole diameter is minimum. 4A and 4B are cross-sectional views showing a sizing ring according to one embodiment, in which FIG. 4A is a cross-sectional view showing a state in which the hole diameter is maximum, and FIG. 4B is a perspective view showing a state in which the hole diameter is minimum. 5A and 5B are diagrams showing an example of a movable member, in which FIG. 5A is a perspective view and FIG. 5B is a cross-sectional view. 6A and 6B are diagrams showing another example of a movable member, in which FIG. 6A is a perspective view, FIG. 6B is a perspective view seen from a different direction from FIG. 6A, and FIG. 6C is a view seen from the radially outward direction of the sizing ring.

Embodiments of the present invention will be described below with reference to the drawings. Note that identical or corresponding components in each drawing will be assigned the same reference numerals, and descriptions thereof may be omitted. In this specification, the X-axis, Y-axis, and Z-axis directions are perpendicular to one another. The X-axis and Y-axis directions represent the horizontal direction, and the Z-axis direction represents the vertical direction.

With reference to Figure 1, an inflation molding apparatus 1 according to one embodiment will be described. The inflation molding apparatus 1 comprises a die 10, a first cooling device 20, a second cooling device 30, a pair of stabilizers 40, and a pinch roll 50. The inflation molding apparatus 1 is a downward-facing type in which resin is extruded downward from the die 10. However, the present invention is also applicable to an upward-facing type inflation molding apparatus in which resin is extruded upward from the die 10.

Molten resin is supplied to the die 10 from an extruder (not shown). The supplied molten resin is extruded from a ring-shaped resin outlet 11 formed in the die 10. Air is appropriately sprayed into the extruded molten resin from air outlets 12 formed inside the resin outlet 11. This forms a bubble B, which is a tubular resin film.

The first cooling device 20 is positioned below the die 10. The first cooling device 20 sprays cooling gas onto the bubbles B to cool them. The second cooling device 30 is positioned below the first cooling device 20. The second cooling device 30 cools the bubbles B by bringing cooling water into contact with the bubbles B. Details of the second cooling device 30 will be described later. The bubbles B are cooled by the first cooling device 20 and the second cooling device 30 and solidify.

A pair of stabilizer plates 40 are positioned below the second cooling device 30 and guide the bubble B between a pair of pinch rolls 50. The pair of pinch rolls 50 are positioned below the stabilizer plates 40. The pair of pinch rolls 50 pull down the guided bubble B, folding it flat. The winder 60 winds up the folded resin film to form a film roll R.

An example of the second cooling device 30 will be described with reference to Figure 2. The second cooling device 30 includes a water tank 31, a sizing ring 32, a first cylindrical member 33, a second cylindrical member 34, and a rotation mechanism 35. The water tank 31 stores cooling water to be supplied to the sizing ring 32. The sizing ring 32 determines the outer diameter of the bubbles B. The sizing ring 32 has an insertion hole 32a through which the bubbles B pass. The first cylindrical member 33 is placed on the bottom 31a of the water tank 31 and supports the sizing ring 32 at a predetermined height from the bottom 31a of the water tank 31. The second cylindrical member 34 extends downward from the bottom 31a of the water tank 31 and surrounds the bubbles B to prevent the cooling water from scattering. The rotation mechanism 35 rotates the sizing ring 32.

The water tank 31 is circular in plan view, although not limited thereto, and has an open top. The bottom 31a of the water tank 31 has a through-hole 31b through which the bubbles B pass. The bottom 31a of the water tank 31 also has a cooling water supply port 31c. The bottom 31a of the water tank 31 also has an overflow pipe 36 attached. The overflow pipe 36 extends above the sizing ring 32 and has an outlet 36a at its upper end. Cooling water is supplied through the supply port 31c and discharged through the outlet 36a. The cooling water level WH is determined by the position of the outlet 36a and is maintained at a predetermined level above the sizing ring 32. A cooling water film is formed between the wall surface of the through-hole 32a of the sizing ring 32 and the bubbles B. The cooling water cools the bubbles B as it flows between the wall surface of the through-hole 32a and the outer periphery of the bubbles B.

A plurality of (e.g., four) plates 37 are fixed to the outer peripheral surface 31d of the water tub 31. A first bolt 71 is threaded vertically downward into each of the plurality of plates 37. The first bolts 71 are provided, for example, at equal intervals around the circumference. The first bolts 71 pass through the plates 37, and the tips of the first bolts 71 each abut against the upper surface 70a of the mounting base 70. The water tub 31 is supported on the mounting base 70 via the plurality of first bolts 71. The first bolts 71 and plates 37 form a ball screw mechanism, and turning the first bolts 71 moves the plates 37, and therefore the water tub 31, in the vertical direction. In other words, the height of the water tub 31 is adjusted.

A plurality of (e.g., four) support members 73 are fixed to the upper surface 70a of the mounting table 70. Second bolts 72 are threaded horizontally into each of the support members 73 toward the central axis of the water tank 31. The second bolts 72 are arranged, for example, at equal intervals in the circumferential direction. The second bolts 72 pass through the support members 73, and the tips of the second bolts 72 each abut against the outer peripheral surface 31d of the water tank 31. The water tank 31 is positioned horizontally by the plurality of second bolts 72. For example, the water tank 31 is positioned horizontally so that the central axis of the sizing ring 32 coincides with the central axis of the resin discharge port 11 of the die 10.

The sizing ring 32 is a component that determines the outer diameter of the bubble B based on the diameter of the insertion hole 32a. A film of cooling water is formed between the wall surface of the insertion hole 32a and the bubble B. Therefore, the outer diameter of the bubble B is smaller than the diameter of the insertion hole 32a by the thickness of the cooling water film. As will be described in detail later, the sizing ring 32 is equipped with a hole diameter variable mechanism 100 (see Figure 3) that changes the hole diameter of the insertion hole 32a. This eliminates the need to replace the sizing ring 32 when changing the outer diameter of the bubble B. Note that coolants other than cooling water may be used. Furthermore, a cooling gas may be used as a refrigerant instead of a coolant.

The first cylindrical member 33 is disposed so that its central axis extends vertically. The lower end of the first cylindrical member 33 is spigot-fitted to the bottom 31a of the water tank 31. The sizing ring 32 is placed on the upper end of the first cylindrical member 33. In other words, the sizing ring 32 is supported by the first cylindrical member 33. The upper end of the first cylindrical member 33 is spigot-fitted to the sizing ring 32, specifically the second retaining member 132 described below.

The second cylindrical member 34 extends downward from the bottom 31a of the water tank 31. The second cylindrical member 34 has the same inner diameter as the insertion hole 31b of the water tank 31, and by surrounding the bubble B, prevents the cooling water from splashing.

The rotation mechanism 35 rotates the sizing ring 32. The rotation mechanism 35 rotates the sizing ring 32, for example, once every 20 to 30 minutes. The sizing ring 32 is rotated when the insertion hole 32a of the sizing ring 32 is not a perfect circle. When the insertion hole 32a is not a perfect circle, the distance between the wall surface of the insertion hole 32a and the bubbles B varies circumferentially around the insertion hole 32a. In areas with wider distances, a larger amount of cooling water flows than in areas with narrower distances, and the time it takes for the bubbles B to solidify is shorter. In areas where the bubbles B take less time to solidify, they are less likely to be stretched by the pair of pinch rolls 50 and are more likely to become thicker than in areas with longer distances. As a result, the thickness of the bubbles B becomes uneven in the circumferential direction of the bubbles B.

The rotation mechanism 35 rotates the sizing ring 32, causing the thick and thin portions of the bubble B to rotate in the circumferential direction of the bubble B. This prevents the thick portions of the bubble B from piling up on top of each other when the winder 60 forms the film roll R, and also prevents the thin portions of the bubble B from piling up on top of each other. This prevents unevenness from forming on the outer periphery of the film roll R, and prevents distortion of the resin film.

The rotation mechanism 35 may rotate the sizing ring 32 by rotating the water tank 31. By rotating the sizing ring 32 together with the water tank 31, it is not necessary to place the components of the rotation mechanism 35 inside the water tank 31, and swaying of the cooling water inside the water tank 31 can be suppressed. As a result, uneven thickness of the bubble B caused by swaying of the cooling water inside the water tank 31 can be prevented.

The rotation mechanism 35 includes, for example, a drive unit 80 and a transmission mechanism 81. The drive unit 80 is, for example, a motor or gear motor, and outputs rotational force. The transmission mechanism 81 is a mechanism that transmits the rotational force generated by the drive unit 80 to the water tub 31, and includes an external gear 82 and a bearing 83. The external gear 82 is fitted to the output shaft 80a of the drive unit 80.

The bearing 83 is positioned to surround the bubble B. The central axis of the bearing 83, the central axis of the sizing ring 32, and the central axis of the water tank 31 are substantially aligned.

The bearing 83 includes an inner ring 83a and an outer ring 83b. The inner ring 83a is fixed to a frame (not shown). The outer ring 83b is fixed to the water tank 31. The outer ring 83b is indirectly fixed to the water tank 31 by being fixed to the mounting base 70, but it may also be fixed directly to the water tank 31. External teeth 83c that mesh with the external gear 82 are formed on the outer periphery of the outer ring 83b.

When the external gear 82 rotates in conjunction with the rotation of the output shaft 80a, the outer ring 83b rotates. As described above, the outer ring 83b is fixed relative to the water tank 31. The sizing ring 32 is also fixed relative to the water tank 31. Therefore, when the outer ring 83b rotates, the sizing ring 32 rotates.

The rotation mechanism 35 preferably rotates (i.e., rotates back and forth) the water tank 31 within a predetermined angular range (e.g., a predetermined angular range of 360° or less). This prevents twisting of the hose (not shown) connected to the supply port 31c.

An example of a hole diameter variable mechanism 100 for the sizing ring 32 will be described with reference to Figures 3 to 5. As shown in Figures 3 and 4, the hole diameter variable mechanism 100 changes the hole diameter of the insertion hole 32a. The hole diameter variable mechanism 100 has multiple (e.g., 32) movable members 110 that define the insertion hole 32a, arranged continuously in the circumferential direction of the insertion hole 32a. The movable members 110 can move in both directions, to decrease the hole diameter and to increase the hole diameter.

The insertion hole 32a of the sizing ring 32 is defined by multiple movable members 110, and the side surfaces of the multiple movable members 110 form the wall surface of the insertion hole 32a. The height of the wall surface of the insertion hole 32a is determined by the height of the movable members 110. The height of the wall surface is set to a height sufficient to determine the outer diameter of the bubble B.

As shown in FIG. 5, the movable member 110 has a blade 111 that is, for example, triangular prism-shaped. The blade 111 has an upper surface 111a, a lower surface 111b, a first side surface 111c, a second side surface 111d, and a third side surface 111e. The upper surface 111a and the lower surface 111b are triangular and tapered toward the radial inside of the sizing ring 32. The first side surface 111c, the second side surface 111d, and the third side surface 111e are rectangular.

A first protrusion 121 is provided on the upper surface 111a of the blade 111. The first protrusion 121 is inserted into a first slit 131a (see Figure 3) of the first holding member 131. Meanwhile, a second protrusion 122 is provided on the lower surface 111b of the blade 111. The second protrusion 122 is inserted into a second slit 132a (see Figure 4) of the second holding member 132. The first protrusion 121 and second protrusion 122 are arranged on the same vertical line.

The hole diameter changing mechanism 100 has a first holding member 131. The first holding member 131 holds the blade 111 so that it can move freely in a direction that changes the hole diameter of the insertion hole 32a. The first holding member 131 is a thin, annular member. The first holding member 131 has the same number of first slits 131a as the number of blades 111 formed at equal intervals around the circumference. When viewed from above, the first slits 131a extend linearly and are inclined counterclockwise as they move radially inward of the sizing ring 32.

The hole diameter changing mechanism 100 also has a second holding member 132. The second holding member 132 holds the blade 111 so that it can move freely in a direction that changes the hole diameter of the insertion hole 32a. The second holding member 132 is a member having the same shape and size as the first holding member 131. That is, the second holding member 132 is a thin-walled, annular member. The second holding member 132 has the same number of second slits 132a as the number of blades 111 formed at equal intervals in the circumferential direction. When viewed from above, the second slits 132a extend linearly and are inclined clockwise as they move radially inward of the sizing ring 32. That is, when viewed from above, the second slits 132a are inclined in the opposite direction to the first slits 131a.

As shown in Figure 4, the first side surface 111c of one blade 111 contacts the second side surface 111d of the adjacent blade 111. The first side surface 111c and the second side surface 111d are sliding surfaces and are vertical planes. When viewed from above, the first side surface 111c and the second side surface 111d incline clockwise as they move radially inward of the sizing ring 32. Multiple blades 111 overlap in the radial direction of the sizing ring 32.

When the first holding member 131 is rotated clockwise relative to the second holding member 132 as viewed from above, the first protrusion 121 moves radially inward along the first slit 131a, and the second protrusion 122 moves radially inward along the second slit 132a. As a result, the blade 111 moves radially inward, reducing the diameter of the insertion hole 32a in the sizing ring 32.

On the other hand, when the first holding member 131 is rotated counterclockwise relative to the second holding member 132 as viewed from above, the first protrusion 121 moves radially outward along the first slit 131a, and the second protrusion 122 moves radially outward along the second slit 132a. As a result, the blade 111 moves radially outward, and the diameter of the insertion hole 32a of the sizing ring 32 increases.

Here, we have described the case where the first holding member 131 is rotated relative to the second holding member 132, but the second holding member 132 may also be rotated relative to the first holding member 131.

In addition, while the case where the first side surface 111c and the second side surface 111d are inclined clockwise as they move radially inward of the sizing ring 32 when viewed from above has been described, the first side surface 111c and the second side surface 111d may also be inclined counterclockwise as they move radially inward of the sizing ring 32 when viewed from above. In the latter case, the first slit 131a is inclined clockwise as it moves radially inward of the sizing ring 32. In addition, in the latter case, the second slit 132a is inclined counterclockwise as it moves radially inward of the sizing ring 32.

However, when multiple blades 111 are moved in a direction that changes the diameter of the insertion hole 32a, gaps may occur between the sliding surfaces of adjacent blades 111. One possible cause of these gaps is that, when viewed from above, the blades 111 may rotate around the first protrusion 121 and the second protrusion 122. If cooling water leaks out of the resulting gaps, a uniform film of cooling water will not form between the wall surface of the insertion hole 32a and the bubble B, resulting in molding defects.

As shown in Figures 4 and 5, the blade 111 includes a separation limiting portion 112 that limits the separation between adjacent blades 111. By limiting the separation between the sliding surfaces of adjacent blades 111 using the separation limiting portion 112, it is possible to prevent gaps from forming between the sliding surfaces. This prevents cooling water from leaking through the gap, allows a uniform film of cooling water to be formed between the wall surface of the insertion hole 32a and the bubble B, and reduces molding defects.

For example, the separation restriction portion 112 includes an adsorption portion 113 that adsorbs adjacent blades 111. The adsorption portion 113 generates an adsorption force in a direction intersecting the boundary between the first side surface 111c and the second side surface 111d, thereby restricting the formation of a gap between the first side surface 111c and the second side surface 111d. The multiple blades 111 can move against the adsorption force in a direction that changes the diameter of the insertion hole 32a.

The suction portion 113 may suction multiple blades 111 together. For example, the suction portion 113 may suction a blade 111 that is far away, thereby suctioning an adjacent blade 111. Therefore, not all blades 111 may include a suction portion 113. For example, blades 111 that include a suction portion 113 and blades 111 that do not include a suction portion 113 may be arranged alternately in the circumferential direction of the sizing ring 32.

The attraction portion 113 includes, for example, a magnet 113A. The magnetic force of the magnet 113A can generate an attraction force. The magnet 113A may be a permanent magnet or an electromagnet. In the case of a permanent magnet, no electrical wiring is required. On the other hand, in the case of an electromagnet, the generation and disappearance of the attraction force can be controlled by controlling the current supplied to the electromagnet. For example, the attraction force can be disappeared when the diameter of the insertion hole 32a is changed, and the attraction force can be generated when the diameter of the insertion hole 32a is fixed.

As shown in FIG. 5, the blade 111 may include a first cover member 114 and a second cover member 115 in addition to the magnet 113A. The first cover member 114 and the second cover member 115 are fastened together with fasteners such as bolts (not shown) to form a triangular prism-shaped member. The first cover member 114 and the second cover member 115 house the magnet 113A inside. The magnet 113A is plate-shaped.

The first cover member 114 is a triangular prism-shaped member. The second cover member 115 is a member that integrates a triangular prism-shaped member of approximately the same size as the first cover member 114 with a square prism-shaped member whose upper and lower surfaces are trapezoidal.

When the diameter of the insertion hole 32a is at its maximum as shown in Figure 4(A) or its minimum as shown in Figure 4(B), the size and position of the magnet 113A are determined so that when one magnet 113A is projected in its magnetization direction when viewed from above, it overlaps at least a portion of the adjacent magnet 113A. In Figure 4, the magnetization direction of each magnet 113A is perpendicular to the longitudinal direction of each magnet 113A.

Although only a portion of the blade 111 is magnet 113A, the entire blade may be magnetized. Furthermore, not all blades 111 need include magnets 113A; blades 111 that include magnets 113A and blades 111 that do not include magnets 113A may be arranged alternately around the circumference of the sizing ring 32. Blades 111 that do not include magnets 113A preferably include a soft magnetic material such as iron instead of magnets 113A (hard magnetic material). The soft magnetic material is attracted by the magnets 113A.

In this embodiment, magnetic force is used as the suction force of the suction portion 113, but vacuum suction force can also be used.

With reference to Figure 6, a modified example of the separation limiting portion 112 will be described. As shown in Figure 6, the separation limiting portion 112 may include an engaging portion 116 that engages with an adjacent blade 111. The engaging portion 116 uses an engaging protrusion 116A and an engaging groove 116B. The engaging protrusion 116A is provided linearly on the second side surface 111d, and the engaging groove 116B is provided linearly on the first side surface 111c. The engaging protrusion 116A and the engaging groove 116B each have a T-shaped cross section, but may also have an L-shaped cross section. There is no particular limitation on the cross-sectional shape.

The engagement protrusion 116A on the second side surface 111d of one blade 111 and the engagement groove 116B on the first side surface 111c of the adjacent blade 111 engage with each other, limiting the separation between the adjacent blades 111. The engagement protrusion 116A and the engagement groove 116B are capable of relative longitudinal movement while engaged with each other. This allows the adjacent blades 111 to move in a direction that changes the diameter of the insertion hole 32a.

The arrangement of the mating protrusion 116A and mating groove 116B may be reversed, with the mating protrusion 116A provided on the first side surface 111c and the mating groove 116B provided on the second side surface 111d. In any case, if all blades 111 have the same shape, the manufacturing and management costs of the blades 111 can be reduced.

It is not necessary for all blades 111 to have the same shape. Blades 111 having mating protrusions 116A on both the first side surface 111c and the second side surface 111d and blades 111 having mating grooves 116B on both the first side surface 111c and the second side surface 111d may be arranged alternately around the circumference of the sizing ring 32.

Although not shown, the mating protrusion 116A and mating groove 116B may be provided on the upper surface 111a or the lower surface 111b. For example, a mating groove 116B may be provided on the upper surface 111a of one blade 111, and a mating protrusion 116A that is inserted into the mating groove 116B from above may be provided on the upper surface 111a of an adjacent blade 111.

However, it is preferable that the fitting protrusion 116A and fitting groove 116B be provided on the first side surface 111c or the second side surface 111d. This allows the fitting protrusion 116A and fitting groove 116B to be hidden inside the sizing ring 32, preventing disruption to the flow of cooling water.

The separation restriction portion 112 may include only one of the suction portion 113 and the fitting portion 116, or it may include both.

The above describes embodiments of the inflation molding apparatus, sizing ring of the inflation molding apparatus, and movable member of the sizing ring of the inflation molding apparatus according to the present invention, but the present invention is not limited to these embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present invention.

1 inflation molding device 32 sizing ring 32a insertion hole 100 hole diameter variable mechanism 110 movable member 112 separation limiting portion B bubble

Claims (10)

An inflation molding apparatus including a sizing ring that forms a through hole through which a bubble passes,
the sizing ring includes a hole diameter varying mechanism that varies the hole diameter of the insertion hole,
the hole diameter varying mechanism has a plurality of movable members that define the insertion hole and are arranged continuously in a circumferential direction of the insertion hole,
the movable member includes a separation limiting portion that limits a separation between the movable member and an adjacent movable member,
The distance limiting portion limits the distance between the sliding surfaces of the adjacent movable members . An inflation molding apparatus including a sizing ring that forms a through hole through which a bubble passes,
the sizing ring includes a hole diameter varying mechanism that varies the hole diameter of the insertion hole,
the hole diameter varying mechanism has a plurality of movable members that define the insertion hole and are arranged continuously in a circumferential direction of the insertion hole,
the movable member includes a separation limiting portion that limits a separation between the movable member and an adjacent movable member,
The distance limiting portion includes an adsorption portion that adsorbs the adjacent movable member . The inflation molding device of claim 2, wherein the suction portion includes a magnet. An inflation molding apparatus including a sizing ring that forms a through hole through which a bubble passes,
the sizing ring includes a hole diameter varying mechanism that varies the hole diameter of the insertion hole,
the hole diameter varying mechanism has a plurality of movable members that define the insertion hole and are arranged continuously in a circumferential direction of the insertion hole,
the movable member includes a separation limiting portion that limits a separation between the movable member and an adjacent movable member,
The separation limiting portion includes a fitting portion that fits with an adjacent movable member . A sizing ring of an inflation molding apparatus,
Equipped with a variable hole diameter mechanism that changes the diameter of the insertion hole through which the bubble passes,
the hole diameter varying mechanism has a plurality of movable members that define the insertion hole in a circumferential direction of the insertion hole,
the movable member includes a separation limiting portion that limits a separation between the movable member and an adjacent movable member,
The separation limiting portion is a sizing ring of an inflation molding device that limits the separation between the sliding surfaces of adjacent movable members . A sizing ring of an inflation molding apparatus,
Equipped with a variable hole diameter mechanism that changes the diameter of the insertion hole through which the bubble passes,
the hole diameter varying mechanism has a plurality of movable members that define the insertion hole in a circumferential direction of the insertion hole,
the movable member includes a separation limiting portion that limits a separation between the movable member and an adjacent movable member,
The sizing ring of the inflation molding apparatus, wherein the separation limiting portion includes an adsorption portion that adsorbs the adjacent movable member . A sizing ring of an inflation molding apparatus,
Equipped with a variable hole diameter mechanism that changes the diameter of the insertion hole through which the bubble passes,
the hole diameter varying mechanism has a plurality of movable members that define the insertion hole in a circumferential direction of the insertion hole,
the movable member includes a separation limiting portion that limits a separation between the movable member and an adjacent movable member,
The sizing ring of the inflation molding apparatus, wherein the separation limiting portion includes a fitting portion that fits with the adjacent movable member . A movable member of a sizing ring of an inflation molding device, comprising: a sizing ring that forms a through-hole through which a bubble passes; the sizing ring having a hole diameter varying mechanism that varies the hole diameter of the through-hole; and the hole diameter varying mechanism having a plurality of movable members that define the through-hole in a circumferential direction of the through-hole,
the movable member includes a separation limiting portion that limits a separation between the movable member and an adjacent movable member,
The separation limiting portion is a movable member of a sizing ring of an inflation molding apparatus that limits the separation between the sliding surfaces of adjacent movable members . A movable member of a sizing ring of an inflation molding device, comprising: a sizing ring that forms a through-hole through which a bubble passes; the sizing ring having a hole diameter varying mechanism that varies the hole diameter of the through-hole; and the hole diameter varying mechanism having a plurality of movable members that define the through-hole in a circumferential direction of the through-hole,
the movable member includes a separation limiting portion that limits a separation between the movable member and an adjacent movable member,
The movable member of a sizing ring of an inflation molding apparatus , wherein the separation limiting portion includes an adsorption portion that adsorbs the adjacent movable member . A movable member of a sizing ring of an inflation molding device, comprising: a sizing ring that forms a through-hole through which a bubble passes; the sizing ring having a hole diameter varying mechanism that varies the hole diameter of the through-hole; and the hole diameter varying mechanism having a plurality of movable members that define the through-hole in a circumferential direction of the through-hole,
the movable member includes a separation limiting portion that limits a separation between the movable member and an adjacent movable member,
The movable member of a sizing ring of an inflation molding apparatus, wherein the separation limiting portion includes a fitting portion that fits with an adjacent movable member .