JP2003225940A - Preform holding fixture for biaxial stretch blow molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set extension of a flow channel of air into a preform as a technical subject to obtain the high productivity of a biaxially stretched blow-molded bottle body. <P>SOLUTION: A cylindrical fixture main body has a pin insertion hole permitting the insertion of a stretching pin formed to the center thereof in a piercing state. A mouth cylindrical part of the preform made of a synthetic resin having a bottomed cylindrical shape is fitted in the leading end of the fixture main body up to a fitting-in limit to hold the preform and, in this state, all of constituent regions are positioned so as to be separated at least by the length corresponding to the half of the inner diameter of the mouth cylindrical part. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a preform holding jig used in a biaxial stretch blow molding method for synthetic resin bottles.

[0002]

2. Description of the Related Art A biaxially stretched blow molded bottle made of a synthetic resin, especially a biaxially stretched blow molded bottle made of a polyethylene terephthalate resin exhibits many excellent characteristics.
Widely used in many ways as a bottle container.

This biaxially stretched blow molding bottle made of synthetic resin is a preform which is injection-molded into a cylindrical shape having a bottom and is heated to a temperature at which a stretching effect can be exhibited, in the axial and radial directions. It is generally formed by stretching and deforming.

That is, as shown in FIG. 10, a preform P, which is held by a holding jig 5 in a state where it is loosely fitted to a guide cylinder 10 in an upright posture and heated to a temperature at which a stretching effect is exhibited, A state in which the neck ring P1 integrally provided around the lower end of the outer peripheral surface of the mouth tube portion P2 of the preform P is locked to the neck support collar portion 3 of the blow die 1 together with the holding jig 5 in the blow die 1. And stretched in the axial direction by the extension pin 16 inserted through the pin insertion hole 11 formed through the center of the holding jig 5, and is blown by the blow air pressed through the pin insertion hole 11 or the extension pin 16. It is stretched and molded in the radial direction to achieve molding into a bottle P '.

In the above-mentioned conventional method, the posture of the preform is ensured mainly by the guide tube portion 10 fitted in the mouth tube portion P2.

[Problems to be Solved by the Invention]

However, in the conventional method in which the guide tubular portion is fitted into the mouth tubular portion of the preform and the assembly posture of the preform is maintained, the guide tubular portion can be used as a flow path for blow air. There is a problem that the effective sectional area inside the mouth tube portion of the preform becomes small, the flow rate of blow air is increased, and the blow time is shortened.

Further, immediately after blow molding, there are many steps for cooling the bottle body by air circulation for blowing air into the bottle body, which is mainly carried out through an air flow path provided in the drawing pin. It is required to increase the air flow path to increase the flow rate of air, improve the cooling efficiency, and further improve the productivity.Here, the reduction of the effective cross-sectional area of the mouth cylinder is also a problem. Has become.

Therefore, the present invention was devised in order to solve the above-mentioned problems in the prior art, and the technical problem was to expand the air flow path into the preform.
The purpose is to obtain high productivity of axially stretch blow molded bottles.

[0009]

[Means for Solving the Problems] [Means for Solving the Problems] Among the present invention for solving the above technical problems, the means for carrying out the invention according to claim 1 is a cylindrical shape having a pin insertion hole through which an extension pin is inserted, formed through the center thereof. Having a jig body of, the tip of this jig body,
With the mouthpiece of the bottomed cylindrical synthetic resin preform fitted to the insertion limit, and with this preform held, all components are at least the mouthpiece part from the center axis of the preform. It is configured to be positioned apart by half the length of the inner diameter.

According to the above-mentioned structure of the present invention, in the state in which the preform is held, all the constituent parts are located away from the center axis of the preform by at least half of the inner diameter of the mouth tube portion. So that is, inside the mouthpiece,
Also, the pin insertion hole of the jig body, which is the air supply flow path to the inside of the preform, does not have any part that obstructs the flow of air into the preform, so the air flow path can be widened to the limit. It is possible to improve productivity by shortening the blow time by increasing the flow rate of blow air and improving the cooling efficiency by increasing the flow rate of air during air circulation. .

Usually, the air blow in blow molding and the air circulation for cooling the bottle after the blow are carried out with the stretching pin inserted through the holding jig and the preform, and in the air blow, the stretching pin is mainly used. Blow air flows through the gap between the outer peripheral surface and the inner peripheral surface of the mouth tube into the preform, and during air circulation, air flows through the passage formed in the stretch pin,
Depending on the purpose, the effective cross-sectional area available for the flow of blow air or circulation air can be determined mainly by the outer diameter of the drawing pin.

Further, by inserting the mouth tube portion to the tip end portion of the jig body up to the insertion limit, at least the preform is upside down, and the posture of the preform is adjusted when the preform is inserted into the jig body. Can be held.

The fitting limit of the mouth tube portion is, for example, a neck ring integrally provided around the lower end of the outer peripheral surface of the mouth tube portion, or the upper end portion of the mouth tube portion and the tip surface of the jig body, and further appropriately attached. It can be set by circumferential contact with the circumferential step.

According to a second aspect of the present invention, in the first aspect of the invention, the tip portion of the jig main body is formed into a cylindrical shape having an inner diameter that loosely contacts the mouth tube portion of the preform. .

According to the above-mentioned structure of the present invention, since the inner peripheral surface of the tip portion of the holding jig is loosely in contact with the mouth tube portion of the preform, at least the preform is upside down and fitted into the jig body. With respect to the posture, it is possible to maintain the posture of the preform, and it is possible to easily insert and pull out the mouth tube from the tip of the jig body. It is possible to adjust the strength of circumscribing, which is related to the holding property and the insertion and withdrawal properties, by setting the inner diameter of the tip portion of the jig body.

According to a third aspect of the present invention, in the first or second aspect of the invention, the cover portion is provided on the inner peripheral surface of the tip portion of the jig body at a position facing the cover portion of the mouth tube portion of the preform. The outer periphery of the above is provided with a support portion which is circumscribed so that the mouth tube portion can be inserted and withdrawn, and which holds the posture of the preform.

According to the above structure of claim 3, the supporting portion provided on the inner peripheral surface of the holding jig enables the mouth tube portion of the preform to be inserted and withdrawn, which is necessary in the process of manufacturing the bottle. Depending on the situation, this insertion and extraction can be performed.

Further, the support portion is configured to hold the posture of the preform while circumscribing the outer periphery of the cover portion of the preform, and, of course, when the support portion is attached to the blow mold,
Even when the holding jig is removed from the blow mold, the support portion can securely hold the posture of the preform, and it is possible to suppress the swinging of the preform, so that the posture can be maintained during transportation. It is possible to prevent production troubles due to the shift.

According to a fourth aspect of the invention, in the invention of the third aspect, the O-ring is assembled and fixed to the inner peripheral groove formed on the inner peripheral surface of the jig body to form the support portion. ,
It is in.

With the above-mentioned structure according to the fourth aspect, the mouth tube portion can be easily fitted in and pulled out while sliding on the O-ring, and the O-ring is circumscribed over the entire outer circumference of the turnip portion. Therefore, the posture of the preform can be held properly and stably, and the structure of the support portion can be simplified.

According to a fifth aspect of the present invention, in the third aspect of the invention, the holder spring is assembled and fixed to an inner peripheral groove formed on the inner peripheral surface of the jig body to form a supporting portion. ,It is in.

With the above-mentioned structure according to the fifth aspect, it is possible to easily insert and withdraw the mouth tube portion of the preform by utilizing the function of the holder spring, and by making external contact with the turnip portion, By the elastic force of the holder spring set to the desired value, the posture of the preform can be held properly and stably.

According to a sixth aspect of the present invention, in the third aspect of the invention, the jig body has an opening on the inner peripheral surface of the tip end cylinder wall,
A spherical body with a smooth surface cannot be pulled out into a horizontal hole formed in at least three locations at approximately equal center angular intervals with respect to the central axis of the jig body, and a part is projected while being pressed by an elastic body. In this state, the support portion is provided by installing the seal portion that exhibits a sealing property against blow air in the lateral hole.

According to the above structure of claim 6, the ball plunger-like function is utilized, and the sphere moves in the lateral hole in a pressed state, and by the action of rotation of the sphere or the like, the preform mouth tube. The part can be smoothly inserted into or removed from the holding jig, and the preform assembly posture can be reliably maintained by pressing with the elastic body while it is circumscribing the turnip part. By adjusting the repulsive force of the elastic body, it is possible to easily realize proper fitting, withdrawal and posture retention.

As a sphere, there is little deformation due to external force,
It is also possible to use a sphere having good surface slipperiness. For example, a stainless sphere is used, and the elastic body is
For example, an O-ring member having elasticity such as rubber, a coil spring or the like can be used.

The circumscribing position of the above-mentioned O-ring, holder spring or sphere to the turnip portion can be determined according to the purpose and need, but it is more preferable to make contact with the lower end edge of the turnip portion. The lower end edge of the turnip portion exhibits the function of the locking piece, and the posture of the preform can be supported more reliably.

The means of the invention described in claim 7 is the same as in claim 1,
In the invention of 2, 3, 4, 5 or 6, in the state where the jig body is attached to the blow mold, a neck ring integrally provided around the lower end of the outer peripheral surface of the mouth cylinder is attached to the tip opening edge portion of the jig body. This is because it is configured to be in close contact with the contact step provided on the.

With the structure according to the seventh aspect, the upper limit of the neck ring is brought into contact with the contact step portion to determine the fitting limit of the mouth tube portion, and when it is installed in the blow mold,
Since the neck ring of the preform is sandwiched between the contact steps of the blow mold and the jig body, the preform assembly posture relative to the blow mold is fixed.

Further, even when the blow-molded product is removed from the blow mold, the neck ring part is in contact with the contact step part, and the blow-molded product maintains its posture at two positions, the cover part and the neck ring. In particular, the swinging of the blow-molded product in the lateral direction can be reliably suppressed.

Further, by assembling the holding jig to the blow mold, the neck ring of the preform is clamped between the neck supporting collar portion of the blow mold and the contact step portion of the jig body. Since it comes into close contact with the contact step portion, a seal against blow air is achieved.

For this reason, since the neck ring is located at the lower end of the outer peripheral surface of the mouth tube portion of the preform, the whole neck tube portion is located in the blow pressure atmosphere regardless of the outside or the inside thereof. As a result, the blow pressure acts evenly on the entire surface of the mouth tube portion, and it is possible to prevent the occurrence of illegal deformation such as diameter expansion deformation of the mouth tube portion.

The means of the present invention as defined in claim 8 is defined by claim 1,
In the invention of 2, 3, 4, 5, 6 or 7, the outer peripheral surface of the base end portion of the jig body is provided with a locking portion that locks the transfer device in a non-pullable manner.

According to the above structure of claim 8, when a blow-molded product such as a blow-molded bottle is pulled out from the holding jig,
Even if there is resistance from the support part, this locking part ensures the assembly of the jig body to the transfer device, so the jig body does not lift up with the blow molded product and separate from the transfer device. , Can prevent troubles in production.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a blow mold 1 in which a preform P is attached to a holding jig according to the first embodiment of the present invention.
FIG. 2 shows a state in which the extension pin is further inserted, and FIG. 3 shows a state in which the extension pin is further inserted.
2A and 2B are a front view and a plan view of a semi-longitudinal section of the jig body 6, wherein the jig body 6 has a peripheral groove-like locking portion 17 formed on the outer peripheral surface, which is assembled to a carrying device (not shown). The handle cylinder portion 7 having a small outer diameter is provided at the upper end thereof with a fitting cylinder portion 9 which is expanded in outer diameter and which is fitted and fitted into the fitting recess 4 of the blow mold 1.

The handle cylinder portion 7 is a mouth cylinder portion P2 of the preform P.
Has a slightly larger inner diameter than the inner diameter of
The inner diameter of the lower portion is the same as the inner diameter of the handle cylinder portion 7, and the upper portion thereof can be gently circumscribed to the turnip portion P3 via the enlarged diameter portion so that the mouth cylinder portion P2 can be easily fitted.
Further, it has an inner diameter that is gradually tapered upward, and the mouth tube portion P2 of the preform P is fitted into the fitting tube portion 9 from the upper (tip end) opening, and the upper surface of the neck ring P1 is fixed. In a state of being in contact with the contact step portion 13 described later, the mouth tube portion P2
An inner peripheral groove 18a for assembling and holding the O-ring 21 is provided in the upper part of the inner peripheral surface at a height position facing the cover portion P3.

Further, an abutting step portion 13 is formed at the upper end of the fitting tube 9 so as to come into close contact with the upper surface of the neck ring P1, and this abutment determines the fitting limit of the mouth tube portion P2. It is configured so as to exert a sealing effect against blow air, and the mouth tube portion P2 is formed at the time of blow molding.
Is located in the blow pressure atmosphere, so that the blow pressure acts evenly on the entire surface of the mouth tube portion and prevents the mouth tube portion P2 from being deformed such as expanding. can do.

In the first embodiment, the O-ring 21 is assembled and fixed to the inner circumferential groove 18a to form the support portion K, and the O-ring 21 is provided around the mouth tube portion P2 of the preform P. By circumscribing the lower edge of the turnip part P3,
The posture of the preform P is maintained (see FIGS. 1 and 4).

Further, the upper surface of the neck ring P1 is in contact with the contact step portion 13 of the fitting tube portion 9 (see FIG. 4), and the contact portion of the neck ring P1 also corresponds to the preform P. The preform P is in a state of exerting its function of retaining the posture, and as a result, the preform P is supported at the two positions of the cover portion P3 and the neck ring P1 to hold the posture more reliably. With this, swinging can be suppressed.

Further, in a state where the jig body 6 is attached to the blow mold 1, the preform P is held in the posture by the action of the supporting portion K, and the neck ring P1 is held by the contact step portion 13 and the blow mold. Since it is securely sandwiched between the first neck support collar portions 3, the swing of the preform P can be surely suppressed even during the blow stretch molding, and the preform P can be prevented from coming off.

FIG. 2 shows a state in which the extension pin 16 is inserted through the pin insertion hole 11 of the jig body 6. As described above, the preform is formed by the support portion K circumscribing the mouth tube portion P2. Since it is possible to reliably hold the posture of P, it is not necessary to install the guide tube piece 10 for holding the posture inside the preform P as in the conventional example (see FIG. 10), and it is possible to further improve the posture. The handle tube portion 7 of the ingredient body 6 also has an inner diameter slightly larger than the inner diameter of the mouth tube portion P2, and there is no site that hinders the flow of air.

The same applies to other embodiments described later, but as described above, in the first embodiment, since there is no portion that hinders the flow of air into the preform P, the flow path of the air is limited to the limit. That is, it is possible to secure a circular hole-shaped flow path having at least the inner diameter of the mouth tube portion P2.

Here, if the outer diameter of the drawing pin 16 is set to be small, the gap formed between the outer circumference of the drawing pin 16 and the inner circumference of the mouth tube portion P2 becomes large, and the flow rate of blow air becomes large accordingly. However, conversely, it is also possible to increase the diameter of the drawing pin 16 to increase the flow rate of air for air circulation flowing inside the drawing pin 16, and the diameter of the drawing pin 16 is selected according to the purpose. be able to.

Further, when the support portion K as in this embodiment is adopted, there is some resistance when the preform P is pulled out upward from the holding jig 6, but the handle cylinder portion 7 of the jig body 6 has some resistance. By fixing the jig body 6 to the carrying device by using the formed circumferential groove-shaped locking portion 17, this extraction can be achieved easily and surely.

Although the same applies to the second to fourth embodiments to be described later, in the above-described first embodiment, the preform is placed upside down on the jig body 6 in a vertical posture. Although the description is given of the example in which the preform is inserted from the bottom and the posture thereof is maintained, according to the support portion K of the present embodiment, the posture of the preform that can be taken is not limited to this posture, and the preform is placed from below. It is possible to hold the posture in an arbitrary direction depending on the purpose or need such as a posture to be inserted, a posture to be obliquely inserted, or a posture to be inserted from the side. For example, in a continuous production process, the design of each device such as a transfer device or This has the effect of increasing the degree of freedom in arrangement and the like.

In the second embodiment of the present invention, instead of the O-ring 21 in the first embodiment, a holder spring 22 is installed in the inner peripheral groove 18a to form the support portion K. Since the force of the spring exerts a tightening force on the inside, the preform P can be more reliably contacted with the cover portion P3 of the preform P while being circumscribed.
Can be held and the swing can be suppressed.

FIG. 5A shows an example of the holder spring 22. The coil spring is made into an O-ring shape while being rounded, and a part of the inner peripheral portion of the O-ring shape is fitted into the fitting cylinder. With protruding from the inner peripheral surface of the part 9,
The holder spring 22 is fitted in the inner circumferential groove 18a and brought into contact with the lower end of the cover portion P3 for use. FIG. 5B shows another example of the holder spring 22.

The holder spring 22 has a mouth tube portion P.
The optimum shape, elastic force, etc. can be selected according to the purpose while balancing the fitting and withdrawing properties of No. 2, the holding property of the posture of the preform P, the durability and the like.

FIG. 6 shows a jig body 6 according to the third embodiment of the present invention.
3A and 3B are a front view and a plan view of the cover member P of the mouth tube part P2.
An outer peripheral groove 18b for assembling and holding an outer peripheral seal ring 26 having a rubber elastic property is formed on the upper outer peripheral surface of the fitting cylindrical portion 9 so that the spherical body 23 abuts on the lower end edge of 3. From the bottom of the outer peripheral groove 18b, three circular hole-shaped lateral holes 19 penetrating the cylinder wall of the fitting cylindrical portion 9 are formed at three positions at equal center angles with respect to the central axis of the fitting cylindrical portion 9.

In this embodiment, a stainless ball is used as the spherical body 23, and the lateral hole 19 has a shape in which the inner end portion is slightly reduced in diameter. Outer peripheral groove 18b so as to press 23 from the outside
By setting the outer peripheral seal ring 26 on the spherical body 23, the spherical body 23 is pressed by the outer peripheral seal ring 26 and the lower portion thereof is projected from the inner peripheral surface of the fitting tubular portion 9 (see FIG. 7).

Further, the outer peripheral seal ring 26 constitutes a seal portion which exhibits a sealing property against blow air,
Functions to seal blow air.

With the mouth tube portion P2 fitted in the fitting tube portion 9 up to its fitting limit, a part of the spherical body 23 has a cover portion P.
By locking the preform P on the lower end edge of the preform P, the function of holding the posture of the preform P and suppressing the swing can be more reliably exerted, and the preform P is attached and detached as follows.
Due to the action of the rotation of the sphere 23, it can be carried out without great resistance (see FIG. 7).

FIG. 8 shows a fourth embodiment of the present invention, which is a spherical body 23.
FIG. 11 is an explanatory view of another embodiment utilizing the action of the above, in which the plug 24 has a function of pressing the sphere 23 by the spring 24.
Constitutes a seal portion that exhibits a sealing property against blow air, and has a function of sealing blow air.

The function of the sphere 23 as in the third and fourth embodiments is that the ball plunger having a thread on the outer peripheral surface, which is commercially available, has a lateral hole 19 in which the thread is engraved. It can also be achieved by screwing and assembling while holding the seal.

FIG. 9 shows the fifth embodiment of the present invention.
In the embodiment, the support portion K is not adopted, and the jig body 6 is simply used.
Has a cylindrical shape having an inner diameter loosely circumscribing the mouth tube portion P2, and holds the posture of the preform P at least in the posture in which the preform P is upside down and fitted into the jig body 6. can do.

The inner diameter of the fitting tube portion 9 can be gently circumscribed at the upper portion thereof so as to easily fit the mouth tube portion P2, and the diameter is gradually increased upward to form a taper shape. However, the inner diameter and the taper shape can be selected in consideration of the balance between the fitting and withdrawing characteristics of the mouth tube portion P2 to the tip portion of the jig body 6 and the maintainability of the posture.

Even when the support portion K is not used as in the present embodiment, the neck ring P1 is in contact with the contact step portion 13 and the blow die when the jig body 6 is attached to the blow die 1. Since it is securely sandwiched between the neck support collar portions 3 of the mold 1, it is possible to suppress the swing of the preform P during the blowing.

[0057]

Since the present invention has the above-mentioned structure, it has the following effects. According to the first aspect of the present invention, the flow of air into the preform is prevented even in the pin insertion hole of the jig body, which serves as an air supply flow path into the mouth tube portion and the preform. It is a holding jig configured so that there are no parts, it is possible to widen the air flow path to the limit while holding the preform stably, and shorten the blow time by increasing the air flow rate. Further, it is possible to improve the cooling efficiency at the time of air circulation, and it is possible to achieve the improvement in productivity.

According to the second aspect of the present invention, since the inner peripheral surface of the distal end portion of the holding jig is loosely in contact with the mouth tube portion of the preform, at least the preform is inverted and fitted into the jig body. In this posture, the posture of the preform can be maintained, and it is easy to insert and remove the mouth tube portion of the preform from the tip of the jig body.

According to the third aspect of the present invention, the assembled posture of the blow-molded product can be reliably maintained even when the blow-molded product is removed from the blow mold, and the posture shifts during transportation. It is possible to prevent production troubles.

According to the fourth aspect of the invention, the O-ring is in contact with and supports the entire circumference of the cover portion of the mouth tube portion, so that the posture of the preform is properly and stably maintained. And the supporting portion can be easily configured.

According to the fifth aspect of the invention, the posture of the preform can be properly and stably held by the elastic force of the holder spring set to a desired value.

According to the sixth aspect of the present invention, the action of the sphere enables the posture of the preform to be stably maintained, and the mouthpiece of the preform to be inserted and withdrawn safely and reasonably.

According to the seventh aspect of the invention, since the neck ring is also supported, the posture of the preform can be maintained and the swing can be suppressed more reliably.

Further, by achieving the sealing against blow air by the neck ring, the blow pressure acts evenly on the entire surface of the mouth tube portion to prevent the occurrence of illegal deformation such as diameter expansion deformation of the mouth tube portion. be able to.

According to the invention described in claim 8, even if there is resistance due to the support portion when the blow-molded bottle is pulled out from the holding jig, the jig body is transferred by using the engaging portion. By securely fixing to the jig, the jig body will not be lifted up together, and troubles in production can be prevented.

[Brief description of drawings]

FIG. 1 is a left half vertical sectional front view showing a mounting state of a blow mold according to a first embodiment of the present invention.

FIG. 2 is an enlarged longitudinal cross-sectional view of a main part, showing a state in which a first embodiment of the present invention is mounted on a blow mold and a stretch pin is inserted therethrough.

FIG. 3 is a front view and a plan view showing the first embodiment of the present invention.

FIG. 4 is an enlarged vertical cross-sectional view of a main part in a state where a preform is mounted on the first embodiment of the present invention.

FIG. 5 is a plan view showing an example of a holder spring used in the second embodiment of the present invention.

FIG. 6 is a front view and a plan view showing a third embodiment of the present invention.

FIG. 7 is an enlarged vertical cross-sectional view of a main part of the third embodiment of the present invention with a preform attached thereto.

FIG. 8 is an enlarged vertical cross-sectional view of essential parts in a state in which a preform is mounted on the fourth embodiment of the present invention.

FIG. 9 is a left half vertical sectional front view showing a mounting state of a blow mold of a fifth embodiment of the present invention.

FIG. 10 is an enlarged vertical sectional view of an essential part showing a conventional example.

[Explanation of symbols]

1; Blow mold 2; Mold surface 3; Neck support collar 4; Assembly recess 5; Holding jig 6; Jig body 7; Handle tube 9; Fitting cylinder part 10; Guide tube piece 11 ； Pin insertion hole 13; contact step 14; Guide collar piece 16; Drawing pin 17; Locking part 18a; inner circumferential groove 18b; peripheral groove 19; Horizontal hole 21 ； O-ring 22; Holder spring 23; Hard sphere 24; Spring 26; Peripheral seal ring 27; Plug P; Preform P '; Bottle P1; Neck ring P2; Mouth tube P3; turnip part K; Support section

Continued front page    (72) Inventor Masanori Kimura             310 Minorita, Matsudo City, Chiba Yoshino Industry Co., Ltd.             Tokoro Matsudo Factory F-term (reference) 4F208 AG07 AH55 AM03 LA04 LA07                       LB01 LG03 LJ22 LN06 LN07                       LN09

Claims (8)

[Claims] 1. A pin insertion hole (11) through which a stretch pin (16) is inserted.
Has a cylindrical jig body (6) penetratingly formed in the center, and the end tube portion of a bottomed cylindrical synthetic resin preform (P) (P) at the tip of the jig body (6). (P2) to the insertion limit,
In the state where the preform (P) is held, all the constituent parts are located away from the center axis of the preform (P) by at least half the inner diameter of the mouth tube part (P2). A preform holding jig for biaxial stretch blow molding having a structure. 2. The preform holding jig for biaxial stretch blow molding according to claim 1, wherein the tip of the jig body (6) has a cylindrical shape having an inner diameter loosely circumscribing the mouth tube (P2). . 3. A mouth tube part on the inner peripheral surface of the tip part of the jig body (6).
(P3) at a position facing the turnip part (P3) of (P2)
A support part that holds the posture of the preform (P) by circumscribing the mouth tube part (P2) so that the mouth tube part (P2) can be inserted and extracted.
The preform holding jig for biaxial stretch blow molding according to claim 1 or 2, further comprising (K). 4. The support part (K) according to claim 3, wherein the O-ring (21) is assembled and fixed to an inner peripheral groove (18a) formed in the inner peripheral surface of the jig body (6). Preform holding jig for biaxial stretch blow molding. 5. The holder spring is attached to the jig body.
The preform holding jig for biaxial stretch blow molding according to claim 3, wherein the support portion (K) is configured by being fixedly assembled to the inner peripheral groove (18a) formed on the inner peripheral surface of (6). 6. A circular hole shape which is open at the inner peripheral surface of the distal end portion of the jig body (6) and is formed in at least three positions at substantially equal angular intervals with respect to the central axis of the jig body (6). Installed in the lateral hole (19) of the spherical surface (23) with a smooth surface so that it cannot be pulled out, and a part of the spherical body is projected while being pressed by the elastic body,
The biaxially stretch blow-molding preform holding jig according to claim 3, wherein the lateral hole (19) is provided with a seal portion that exhibits a sealing property against blow air. 7. The neck ring (P1) integrally provided around the lower end of the outer peripheral surface of the mouth tube (P2) is attached to the jig body (6) with the jig body (6) attached to the blow mold (1). The biaxial stretch blow molding preform according to claim 1, 2, 3, 4, 5 or 6, wherein the contact step portion (13) provided at the front opening edge portion of (6) is closely contacted. Holding jig. 8. The jig body (6) is provided with an engaging portion (17) on the outer peripheral surface of the base end portion which is fixed to the carrying device so as not to be pulled out. Or the preform holding jig for biaxial stretch blow molding according to 7.