JP2002060229A - Method and device for transporting preform in blow molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely examine the appearance of a preform, to give uniform heating processing to the preform and to keep the uniform heating and softening state of the preform by reducing the influence of outside air. SOLUTION: A propelling chain conveyer 14 hung around propelling sprockets 13 arranged on a substrate 10 and having preform holding body 16 is moved and suspended to propel and stop the preform fitted to and held by the bodies 16 and rotating chains 18 arranged hung around rotating pulleys 17 on the substrate 10 are engaged with the bodies 16 to control the moving velocity of the chains 18 and that of the conveyer 14 to transport the preform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for transferring a preform in blow molding of a hollow molded article. More specifically, the present invention relates to a method for transferring a preform to a predetermined position by repeatedly propelling and stopping the preform. A transfer method and apparatus for making the rotation speed of a preform constant during propulsion and stop.

[0002]

2. Description of the Related Art Blow molding of a hollow molded article is roughly classified into a so-called cold parison method and a hot parison method, and a parison or preform (hereinafter, referred to as a preform) to be used is previously formed into a bottomed shape by injection molding. And those formed into a cylindrical shape by extrusion molding.

[0003] In blow molding, transferring a preform is one of the important operations, and depending on the purpose, the preform is rotated or non-rotated to continuously or intermittently (non-continuously) a conveying path. A transfer method for transferring is adopted.

Various methods are used for transferring the preform in blow molding. Usually, an endless preform conveying path formed by a propulsion sprocket and a propulsion chain conveyor wound around the sprocket is used. It is done in.

[0005] In this method, an endless preform conveying path is formed by hanging a propulsion chain conveyor around a plurality of propulsion sprockets arranged on a base, and a preform is inserted into the propulsion chain conveyor. In addition to providing a preform holding body to be held, a driving source such as a servomotor is connected to the propulsion sprocket, and the propulsion sprocket and the propulsion chain conveyor are rotated and moved so as to be provided on the propulsion chain conveyor. The reform holder and preform are being transferred.

[0006] If necessary, the preform is continuously transferred by continuously rotating and moving the propulsion sprocket and the propulsion chain conveyor, or the propulsion chain conveyor is rotated after a pause.・ The preform is moved intermittently (non-continuously) while repeatedly propelling and stopping.

Further, in the endless preform conveying path, the preform holder is rotated as necessary in the entire area of the propulsion chain conveyor or in a desired area, and the preform fitted and held therein is rotated. It is designed to be able to be transported.

[0008] The rotation of the preform holder is carried out by rotatably mounting the preform holder coaxially with the connecting pins connecting the connecting plates constituting the propulsion chain conveyor, and at the same time as rotating the preform holder below the preform holder. The engaging part provided in the section is engaged with a rotating chain fixed along the transport path, and the propulsion chain conveyor is moved, or the rotation formed along the transport path is performed. It is performed by moving the rotating chain by engaging the engaging portion with a rotating chain wound around a sprocket. The former is a method in which the preform holder engaged with the rotating chain rotates along the rotating chain while the propulsion chain conveyor is moving, and the latter is engaged with the rotating chain. In this method, the preform holder is rotated by the movement of the rotating chain while the rotating chain is moving, regardless of whether or not the propulsion chain conveyor moves.

In the blow molding of a hollow molded product, the preform is rotated intermittently (non-continuously) while the preform is blown with a mold that can be opened and closed at a predetermined position. During molding, the next preform is performed in order to stop the preform.For example, in the blow molding by the cold parison method, the bottomed preform molded in the injection process is endlessly formed. The propulsion chain conveyor is intermittently (discontinuously) transported while being repeatedly moved and paused by a propulsion drive source such as a servomotor or the like, by being fitted and retained in a preform retainer in the shape transport path.

At the same time, in a predetermined area, for example, a preform inspection area, a preform heating area, or a preform blow molding area, the engaging portion at the lower part of the preform holder is moved along the transport path. It engages with a rotation chain wound around a rotation sprocket formed as described above, and moves the propulsion chain conveyor, and also moves the rotation chain to rotate the preform holder and, consequently, the preform.

The rotation in the preform inspection area is an operation for inspecting almost the entire preform, and the uniform rotation allows the appearance inspection and the like performed by optical means to be performed more accurately. . Rotation in the preform heating area is an important operation for uniformly heating and softening the lower part of the preform from the bottom to the bottom. If the rotation becomes uneven, uneven heating of the preform causes the next blow. In this case, good blow molding cannot be performed in the molding step, which may cause a defect in the hollow molded article.

The rotation of the preform before the blow molding, more specifically, after the preform is heated and before the blow mold is inserted, the influence of the outside air is made as uniform as possible by uniformly rotating the preform after the heating and softening. In order to maintain the softened state by heating, it is inserted into a blow mold to perform good blow molding.

[0013]

Usually, since the rotation of the preform is performed for a single purpose processing such as inspection of the preform, heating of the preform, blow molding, etc., the rotating device of the preform is used. Are used that have a single function for that purpose.

On the other hand, since the transfer of the preform takes the molding cycle time into consideration, the conveying path of the preform has a width such as the molding capacity of the hollow molding machine to be used and the shape and size of the hollow molded article to be molded. A rotating part such as a sprocket, a driving body such as a chain conveyor, and a driving source such as a motor having a shifting function are used.

In such a state, if the molding ability of the hollow molding machine is maximized to improve the productivity, the rotation of the preform cannot follow the transfer of the preform in the conveying path, and the rotation of the preform cannot completely follow. Stable or non-uniform rotation may occur, which may cause problems in the preform heating, inspection, blow molding, and other processing.

[0016]

SUMMARY OF THE INVENTION The present invention relates to a preform in which a preform fitted and held in a preform holder formed in a propulsion driving body is repeatedly moved and propelled and stopped while being rotated and transferred to a predetermined position. Transport method,
The propulsion drive is moved and paused to propel the preform.
A rotation drive that engages with the moving speed of the propulsion driver and the preform holder to rotate the preform so that the preform rotates at the same time during the propulsion and when the propulsion is stopped. The preform is intermittently transferred by controlling the moving speed of the body.

A preform transfer apparatus for blow molding in which a preform is rotated and repeatedly propelled and stopped along a transport path to transfer the preform to a predetermined position, wherein the preform is provided on a base. A propulsion drive is hung on the rotating part for rotation, and a propulsion path in which a preform holding body is formed on the propulsion driving body and a rotation part for rotation provided on the base are rotated. A rotating device for a preform comprising a rotating driver engaged with a preform holder, and a propulsion drive source connected to a propulsion rotating unit for controlling a moving speed of the propulsion driver. And a driving source for rotation connected to the rotating part for rotation and capable of controlling the moving speed of the driving body for rotation.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
This will be described with reference to FIGS.

The blow molding apparatus for the hollow molded article is a biaxial stretching blow molding apparatus, and includes a heating line 1 having a heating device 11 for heating the preform P and a molding die 2.
This is an apparatus in which a stretch blow line 2 having a number 1 and the like are independently formed.

As shown in FIG. 1, a heating device 11 and a preform supply device 12 are provided along a heating line 1, and an inspection area (not shown) is provided if necessary.

In the heating line 1, four propulsion sprockets 13 are rotatably arranged on an appropriate base 10, and a propulsion chain conveyor 14 is hung on the sprockets 13 so that the heating line 1 is endless. A convey path is formed. A sprocket 131 for tension is provided on the propulsion chain conveyor 14 by pressing.

The propulsion chain conveyor 14 intermittently (discontinuously) moves under the control of a propulsion drive source 15 such as a variable speed servomotor connected to one of the propulsion sprockets 13. The preform P on the propulsion chain conveyor 14 is intermittently (non-continuously) transferred in the direction of arrow A.

As shown in FIG. 2, the propulsion chain conveyor 14 has a pair of connecting plates 14a of a predetermined length facing each other at a predetermined interval, and both ends thereof are bendably connected by connecting pins 14b. An endless propulsion chain conveyor 14 formed by repeating the connection between the connection plate 14a and the connection pins 14b many times, and the preform P is fitted and held coaxially with the connection pins 14b of the propulsion chain conveyor 14. The preform holder 16 is rotatably mounted, and its moving speed can be changed.

As shown in FIG. 2, the preform holder 16 has a mandrel 16a into which the preform P is fitted and held, and a lower part engages with a rotation chain 18 to rotate the preform holder 16. Engaging portion 16b for causing
Is provided.

The rotation of the preform holder 16a is controlled by the rotation of the preform holder 1 as shown in FIGS. 1, 3 and 4.
An engaging portion 16b provided at a lower portion of 6a is arranged along the propulsion chain conveyor 14, and is arranged in the direction of the heating zone of the preform P. The rotation is performed by moving the rotation chain 18 in the direction of arrow B in the direction indicated by the arrow B. Rotary pulley 17
A rotatable drive source (not shown) such as a servomotor that can change the speed is connected, and the moving speed of the rotary chain 18 can be changed by control of the rotatable drive source.

If necessary, the rotation chain 18 may be extended to the vicinity of the preform supply device 12 to provide a preform inspection area so that an appearance inspection (not shown) can be performed. A heating device 11 is provided along the propulsion chain conveyor 14.

The heating device 11 has an inner surface conforming to the shape of the preform P. The heating device 111 heats the preform by adjusting the temperature thereof according to the intensity of the alternating magnetic flux applied thereto, and the chain conveyor 14 for propulsion. And the like, and a heater 112 composed of a group of heaters vertically disposed facing the heater. In FIG. 1, the preform P is fitted and held in the preform holder 16 of the propulsion chain conveyor 14,
The preform P is transported while rotating by the rotation of the holder 16, and the heating mold 111 and the heater 11 are rotated.
Although the heating and softening are performed by step 2, the heating and softening may be performed by disposing a plurality of heating heaters in parallel without disposing a heating mold.

A preform supply device 12 arranged at the head position of the heating line 1 supplies a preform P injection-molded by an injection molding machine (not shown) outside the heating line 1 to the heating line 1. It is. As shown in FIG. 1, a blow molding device including a molding die 21 and the like, a preform transfer device 3, and a product take-out device 4 along a stretch blow line 2.
Is arranged.

The stretching blow line 2 has substantially the same construction as the heating line 1, and two propulsion sprockets 23 and the like are rotatably disposed on an appropriate base 20 so as to be rotatable. For example, a chain conveyor 24 for propulsion is wound around to form an endless conveying path of the stretch blow line 2.

The propulsion chain conveyor 24 moves intermittently (discontinuously) under the control of a propulsion drive source 25 such as a servo motor connected to one of the propulsion sprockets 23, and The preform P on the conveyor 24 is intermittently (non-continuously) transported in the directions indicated by the arrows.

The propulsion chain conveyor 24 has a pair of connecting plates 24a of a predetermined length facing each other at a predetermined interval as shown in FIG. An endless chain conveyor 24 formed by repeating the connection between the connection plate 24a and the connection pins 24b many times. The preform P is fitted and held coaxially with the connection pins 24b of the propulsion chain conveyor 24. A preform holder 26 is mounted.

If necessary, a preform holder in which the preform is fitted and held is rotatably mounted on an endless propulsion chain conveyor, and a rotation chain is arranged along the conveyor. The preform after heating and softening may be evenly rotated to make the influence of the outside air as uniform as possible so that the preform can be inserted into the blow molding die while maintaining the softening condition under heating.

As shown in FIG. 1, the blow molding device includes a stretching device (not shown) having a molding die 21 and an air blowing nozzle, and a mold clamping device 22 for clamping and opening the molding die 21.
It consists of The molding die 21 is for introducing a preform P heated and softened by the heating device 11 to form a hollow molded product (not shown), and usually includes a pair of dies 21 a having a cavity on the inner surface, 21b face each other to form a set.

A stretching device (not shown) having an air blowing nozzle has an intermediate plate, a pair of stretch rods, a ball screw and the like arranged at predetermined intervals, and the stretch rod is provided with an air blowing nozzle. It is. The stretch rod is operated by rotating and driving the source such as a servo motor, pulley, endless belt, etc., and the ball screw is rotated by the joint / rotational drive. The rotation raises the intermediate plate to which the stretch rod is connected and fixed. (Or descend). (Either is not shown.) Although the description has been given of the air blowing nozzle having the stretching function by the stretch rod, the air blowing nozzle having no stretching function may be used.

The mold clamping device 22 has two links rotatably mounted at 180 degrees opposite to each other on a rotatably supported rotating disk, with one end of one link being centered. It is rotatably mounted on the back surface of one of the platens 22a located therein,
The other end of the other link is rotatably mounted on the rear surface of the platen support plate 22c located on the right side.

The dies 21a and 21b are opposed to each other to form a pair. One of the dies 21a is attached to one platen 22a located at the center, and the other dies 21b is located on the left side. It is attached to the other platen 22b.

It should be noted that a bottom-type elevating device (not shown) for forming the bottom of the bottle is provided.

The preform transfer device 4 includes a heating line 1
Is a device for transferring the preform P heated and softened in Step 1 to the stretching blow line 2, which is bridged and arranged above the heating line 1 and the stretching blow line 2. The plug portion is gripped and raised in the vertical direction, moved in the horizontal direction in that state, and then lowered directly below and transferred onto the stretch blow line 2.

The product take-out device 5 is a device for taking out a hollow molded product blow-molded by the molding die 21 in the stretching blow line 2 out of the line, and is a hollow molded product molded with the plug portion down. After grasping the plug portion of the article with the grasping body, the grasping body is rotated by 180 degrees and the hollow molded article is transferred to a conveyor at a predetermined position.

The endless transfer path constituting the heating line and the stretch blow line is replaced with a propulsion chain conveyor, and an endless metal sheet having a predetermined shape on a base 20 as shown in FIGS. A belt 31 made of rubber or rubber and fibers having a predetermined width and thickness is formed on the inside of the guide 31 with a gap therebetween. Convex projection 3 meshing
An endless conveyance path 3 of a double track type provided with a propulsion belt conveyor 32 having formed therein 2b may be provided.

In the transport path 3, a metal guide 31 having a T-shaped cross section is disposed on the base 20 in a predetermined shape, for example, an elliptical shape, and two propulsion pulleys face the inside of the metal guide 31. 33, and a propulsion drive source 34 such as a servomotor is connected to the pulley 33.
1 to form an interval along the propulsion belt conveyor 32
To form a double orbital endless transport path 3.

Then, the preform moving body 35 is mounted on the metal guide 31 and the propulsion belt conveyor 32, and the preform holding body 351 and the preform P fitted and held in the mandrel 352 are rotated, and the preform moving body 35 is rotated in the direction indicated by the arrow. Transfer in the direction.

The preform moving body 35 is provided with a recessed engagement in which a rotating belt 37 having a convex projection on its lower surface engages a hole 35b formed in a wide substrate 35a via a bearing through a bearing. The preform holder 351 having the portion 353 is fitted, and the metal guide 31 is attached to the back surface of the substrate 35a.
A plurality of rollers 35c are provided, and a hole 35d is formed in a side portion of the substrate 35a for fitting a guide pin 32a protruding from the propulsion belt conveyor 32.

The transfer of the preform moving body 35 to the endless conveying path 3 of the double orbital type is carried out by using a propulsion drive source 34 such as a variable speed servomotor in which a propulsion belt conveyor 32 is connected to a propulsion pulley 33. With intermittent (non-continuous) movement under control, the propulsion belt conveyor 3
The preform moving body 35 engaged via the second guide pin 32a is pulled along the metal guide 31 to the propulsion belt conveyor 32.

This rotating device employs a rotating pulley 36 having a concave portion, a rotating belt 37 having convex protrusions on both surfaces, and a rotating drive source 38 such as a servomotor. Engaging portion 353 with concave portion
, The front convex portion of the rotation belt 37 is engaged,
The convex portion on the back side of the rotating belt 37 is engaged with the concave portion of the rotating pulley 36, and the rotating belt 3 is attached to the rotating pulley 36.
7 is multiplied. It should be noted that a system using a sprocket and a rotation chain including a connecting plate and a connecting pin wound around the sprocket may be used.

Further, the blow molding apparatus used in the present invention is as shown in the drawings as long as it has a heating line having a heater for heating and softening the preform and a stretching blow line having a molding die and the like. A heating line and a stretch blow line may be divided into separate sections, and a heating step and a biaxial stretch blow step (or a blow step without stretching) may be arranged on separate tracks. A molding process in which a heating process and a biaxial stretching blow process (or a blow process without stretching) are arranged on the same track without dividing into lines may be used.

Next, the operation will be described with reference to FIGS.

First, a preform P with a bottom formed by injection molding in an injection step (not shown) is supplied to a preform supply device 12.
And is fitted and held in the preform holder 16 of the heating line 1 having an endless conveyance path. Preform holder 1
6. The preform P fitted and held in the
Heating by moving in the direction of arrow A while rotating by the movement of the propulsion chain conveyor 14 and the rotation chain 18 which are hung on four propulsion sprockets 13 rotatably disposed on It is sent to the device 11.

The transfer of the preform P is performed by moving the propulsion chain conveyor 14 under the control of a propulsion drive source 15 such as a variable speed servomotor connected to the propulsion sprocket 13. 14
Moving speed (V2) depends on the production capacity,
The speed is changed in the range of 0.5 to 35 m / min.

The rotation of the preform P is performed by the movement of the rotation chain 18 in the direction of the arrow B simultaneously with or prior to the movement of the propulsion chain conveyor 14. The moving speed (V1) is the rotational speed (rpm) of the preform P when the propulsion chain conveyor 14 is not moving.
Is a numerical value obtained by adding the moving speed (V2) to the above.

The rotation speed (rpm) of the preform P is
It is calculated based on experiments and rules of thumb.
120 rpm, which is selected according to the purpose of rotation of the preform, the shape and size of the preform, the blow molding cycle time, and the like.

Although the rotation chain is rotated in the direction of arrow B to rotate the preform P in the forward direction (c), the rotation chain is rotated in the direction of arrow B ′. The preform P may be reversely rotated (c ').

The preform P thus heated
Is fitted and held in the preform holding body 26 of the stretch blow line 2 by the preform transfer device 4. Thereafter, the endless conveyance path is transferred toward the inside of the molding die 21 to perform the hollow molding of the preform holder 26 and the preform P.

Subsequently, air is supplied and blown into the preform P introduced into the molding die 21 through an air blowing nozzle, and the preform P is formed into a hollow molded product having a predetermined shape (FIG. (Not shown). After blow molding, the hollow molded product (not shown) is released from the molding die 21, removed from the stretch blow line 2 by the product removal device 5, and integrated as a product.

As described above, the preform transfer device of the present invention repeats propulsion and stop along the transport path while rotating the preform to transfer the preform to a predetermined position, and is provided on a base. A propulsion drive such as a chain conveyor or a belt conveyor is wound around a propulsion rotating part such as a sprocket or pulley, and a preform holder such as a mandrel, carrier, or pin is formed on this propulsion drive. Endless transport path and a rotation drive unit such as a chain or a belt that is engaged with a rotation unit for rotation such as a sprocket or pulley provided on the base and is engaged with the preform holder. And a propulsion drive source such as a servomotor that can control the moving speed of the propulsion drive connected to the propulsion rotation unit, and a propulsion drive source connected to the rotation rotation unit. It is constituted by a rotary drive source, such as a controllable servomotor moving speed of a rotary drive member.

According to the present invention in which the preform is intermittently (non-continuously) transferred to a predetermined position while rotating, the preform is fitted and held in a preform holder formed on a propulsion drive. After that, first, as shown in FIG. 7 (b), a rotation driving source connected to the rotation rotating body is controlled and controlled.
The preform holder is driven to move the rotating driving body under the control of the predetermined moving speed V1a, thereby rotating the preform holder engaged with the rotating driving body to give the preform a predetermined number of revolutions a.

In this state, the driving body for propulsion, which was in the stopped state V2a, is controlled to rotate at a predetermined moving speed V2b to transfer the preform. At this time, the rotation driving body is raised and controlled to the movement speed V1b in accordance with the movement speed of the propulsion drive body to maintain the rotation speed a of the preform.

Subsequently, the propulsion driving body is stopped, and the preform is stopped V2c. Also at this time, the rotational driving body is lowered and controlled to the moving speed V1c in accordance with the moving speed of the propulsion driving body to maintain the preform rotational speed a.

Hereinafter, by repeating this operation, the moving speed of the propulsion driving body and the moving speed of the rotation driving body are controlled so that the rotation speed a of the preform is constant even when the preform is propelled and stopped. Then, the preform is intermittently transferred.

Note that these controls may be performed automatically by inputting a numerical value obtained in advance or a pattern based on the numerical value into a control device such as a computer.

As a result, the preform rotated at a predetermined rotational speed can be used without lowering the rotational speed that occurs when the propulsion driving body is moved as shown in FIG.
It can be intermittently transferred to a predetermined position while maintaining a predetermined rotation speed.

[0062]

According to the transfer of the preform in the blow molding of the present invention, after the preform is fitted and held in the preform holder formed on the propulsion drive, the rotation drive is moved. While rotating the preform, the preform is repeatedly propelled and stopped by moving and resting the propulsion drive, and transferred to a predetermined position, and the movement speed of the propulsion drive and the rotation speed of the rotation drive are determined. , The following effects can be obtained.

That is, while rotating the preform,
Repeated propulsion and stopping, and transferred to a predetermined position,
It is possible to transfer the preform in a stable state without lowering the rotation speed of the preform during the propulsion and when the preform is stopped.

Thus, the appearance of the preform can be more accurately inspected by optical means before molding in the blow molding step of the hollow molded article, and performed by a heater or the like prior to the blow molding. The heat softening of the preform is uniformly heated from the bottom of the preform to the bottom, and good blow molding can be performed.
Furthermore, after the preform is heated and before the blow molding die is inserted, the influence of the outside air is made as even as possible so that the heating softened state is maintained, and the preform is inserted into the blow molding die. Blow molding can be performed.

[Brief description of the drawings]

FIG. 1 is a plan view of a blow molding apparatus according to the present invention.

FIG. 2 is a cross-sectional side view of a main part showing conveyance of a preform heating line of the present invention.

FIG. 3 is a cross-sectional side view of a main part showing conveyance of a heating line including a preform rotating device of the present invention.

FIG. 4 is an enlarged plan view of a main part showing a relationship between a propulsion driving body and a rotation driving body of the preform of the present invention.

FIG. 5 is a plan view showing another embodiment of the blow molding apparatus of the present invention.

FIG. 6 is a cross-sectional side view of a main part showing conveyance of blow molding in FIG.

FIG. 7 is a graph showing a relationship between a moving speed of a driving body for propulsion of a preform, a moving speed of a driving body for rotation, and a rotation speed.

[Explanation of symbols]

 P Preform 1 Heating line 10 Base 13 Propulsion sprocket 14 Propulsion chain conveyor 15 Propulsion drive source 16 Preform holder 16a Mandrel 16b Engagement part 17 Rotary pulley 18 Twist rotation chain 2 Stretch blow line 23 For propulsion Sprocket 24 Propulsion chain conveyor 25 Propulsion drive source 26 Preform holder 30 Double orbital endless transport path 31 Metal guide 32 Propulsion belt conveyor 33 Propulsion pulley 34 Propulsion drive source 35 Preform moving body 351 Preform Holder 352 Mandrel 353 Engagement part 36 Pulley for rotation 37 Belt for rotation 38 Drive source for rotation

Claims (2)

[Claims] 1. A method of transferring a preform in which a preform fitted and held in a preform holding body formed on a propulsion driving body is repeatedly rotated and propelled and stopped to be transferred to a predetermined position. The propulsion drive is moved and paused to propel and stop the preform, and the propulsion drive is moved and the preform is held so that the rotation speed of the preform at the time of propulsion and stoppage is constant. A method of transferring a preform in blow molding, wherein the preform is intermittently transferred by controlling a moving speed of a rotation driving body that engages with a body and rotates the preform. 2. A preform transfer device in blow molding in which propulsion and stop are repeated along a conveyance path while rotating a preform, and the preform is transferred to a predetermined position.
A propulsion drive is hung around a propulsion rotating unit provided on the base, and a preform transport path in which a preform holder is formed on the propulsion drive is provided on the base. A rotation device for a preform, which is a rotation drive unit that is engaged with the preform holder while being hung on the rotation rotation unit, and movement of the propulsion drive unit connected to the propulsion rotation unit. A propulsion drive source for controlling the speed; and a rotation drive source connected to the rotation rotation unit and capable of controlling the moving speed of the rotation drive body. Reform transfer device.