JP3442141B2 - Blow molding equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding apparatus suitable for molding PET bottles and the like. More specifically, the present invention relates to an improvement of a transport mechanism for transporting a preform along a molding line configured to heat the preform, convey it to a stretch molding machine, and take it out as a molded product therefrom. It is a thing.

[0002]

2. Description of the Related Art Molding of molded articles such as PET bottles is carried out by subjecting a preform formed by injection molding to heat treatment and then stretch molding in a stretch molding machine. In such a blow molding apparatus, preforms are sequentially conveyed at a constant feed pitch along a conveyance path to be subjected to respective treatments.

An example of this type of blow molding apparatus is disclosed in, for example, Japanese Patent Publication No. 1-17855. In the device disclosed herein, the preform transfer line has a quadrangular shape, and rectangular parallelepiped transfer units are arranged on this line so that they are sequentially transferred at a constant feed pitch. It has become. Each transport unit has a transfer tool capable of inserting and fixing the mouth of the preform, and the preform is transported by each transport unit with the mouth inserted. Each transport unit receives the preform at the preform receiving portion, passes the molded product to the takeout portion after passing through the heating portion and the stretch molding portion, and then returns to the preform receiving portion in an empty state. Has become. A circular line is also used as the transfer line.

As described above, the conventional conveying mechanism of the blow molding apparatus constitutes a so-called closed type conveying line, and a large number of preform transfer tools are arranged along the line at a constant pitch, and the preform conveying tools are fixed. It is configured to send sequentially at the pitch. Each transfer tool conveys the preform via the heating section and the stretch molding section arranged along the conveying line, passes the molded product to the receiving section via the stretch molding section, and then, returns the preform to an empty state. It is designed to return to the remodeling department. Further, in the heating section, by rotating each transfer tool, the preform can be uniformly heated by radiative heating from only one direction.

[0005]

However, when such a so-called closed type transfer line is used, it is necessary to return each transfer tool to the initial position in an empty state after the molded product is delivered. However, it is not efficient because of the operation loss. In addition, since the transfer tool that moves on the runie needs to be equipped with a rotation mechanism for rotating the preform,
The mechanism also tends to be complicated. Furthermore, a fixing tool is required for fixing the preform at all times with respect to the transfer tool moving on the line. Furthermore, conventionally, each transfer tool moves along the line, and in the stretch molding section, the forming air is supplied to the preform held by the transfer tool. Therefore, it is necessary to form a mechanism for blowing air in each transfer tool, and in this respect also, the mechanism of the transfer tool tends to be complicated.

On the other hand, in a PET bottle or the like, when stretch-molded from a preform, the stretch amount of each part of the preform differs depending on the shape of the molded product. Therefore, the molded product may be partially formed with a thin-walled portion or a thick-walled portion, and it may not be possible to ensure the mechanical strength or the like of the molded product.

In view of the above points, an object of the present invention is to propose a blow molding apparatus having a conveying mechanism which can be manufactured at a low cost with a simple structure. Another object of the present invention is to propose a blow molding apparatus capable of suitably performing stretch molding of a preform by appropriately heating the preform.

[0008]

In order to solve the above-mentioned problems, in the present invention, a heating means for heating a preform having an open end, and a preform after being heated have a predetermined shape. Stretch-molding means for stretch-molding in the biaxial direction so as to obtain the molded article, take-out means for taking out the molded article obtained through the stretch-molding means, and preform stretching through the heating means. In a blow molding device having a conveying means for conveying the obtained molded product from the stretch forming means to the take-out means while conveying the molded article toward the forming means, the conveying means is configured as follows. There is. That is, the transfer means are arranged at regular intervals, and a plurality of transfer tools that can be inserted into the open ends of the preform and the transfer tools are lowered from their initial positions and retracted in the opposite direction to the transfer direction. After that, the preform is sandwiched between the retreating position and the retreating position to move the retreating position to the forward position, and the transfer mechanism moves from the initial position to the retreating position. The holding mechanism is configured to open and deliver the preform to the insertion portion that has reached the retracted position, and the preform is intermittently conveyed at a predetermined feed pitch.

According to this structure, each transfer tool only moves by the feed pitch, and the preform holding mechanism may hold and release the preform at a fixed position. Therefore, the transport mechanism can be easily configured. Here, the holding mechanism can be composed of a plurality of rollers and roller moving means for holding and releasing the preform by relatively approaching and separating the rollers.

Further, in order to uniformly heat the preform in the heating means, it is sufficient to rotate the transfer tool moving in the heating area of the heating means. In this case, it is preferable to rotate the preform for uniform heating even in the state of being held by the holding mechanism, and in order to do so, at least one of the plurality of rollers constituting the holding mechanism should be rotated. A roller rotating means for rotating may be arranged.

Further, generally, the feed pitch of the preform on the conveying path passing through the heating means and the feed pitch of the preform in the stretch molding means are set to be different. In this case, through a power transmission mechanism such as a rack and pinion mechanism, a cam and a link mechanism,
It is preferable to realize the difference in the feed pitch by the driving force from the same driving source from the viewpoint of making the apparatus compact. Instead of this, for example, a plurality of transfer tools that are slidable via compression springs are forcibly brought into close contact with or separated from each other to realize a difference in the feed pitch by the driving force from the same driving source. May be.

On the other hand, in the present invention, the stretching and forming operation in the stretching and forming means can be appropriately performed.
It is characterized in that a temperature adjusting means capable of adjusting the heating temperature of the preform is arranged in the conveying path immediately before the stretch forming means. For example, a temperature equalizing means for adjusting the temperature of the preform to have a temperature distribution suitable for the stretch-molding temperature is provided by blowing air containing humidity set in a predetermined temperature range over the entire preform. I am trying. By doing so, the preform can be accurately adjusted just before the stretch forming so that the preform has an optimum temperature for the stretch forming.

Further, in order to be able to adjust the amount of stretching of each part of the preform, after the preform is adjusted to a uniform temperature, the air containing the humidity set in a predetermined temperature range is partially used. It is preferable to dispose a temperature change giving means for giving a partial temperature change to the preform by spraying. Instead of blowing air partially, a temperature change may be given to the preform by bringing a heat transfer piece set to a predetermined temperature into contact with the preform.

In this way, the amount of stretching of each part of the preform during stretch molding can be adjusted, so that there is an advantage that the wall thickness of each part after molding can be idealized.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show the overall construction of a blow molding apparatus to which the present invention is applied. The blow molding apparatus 1 of this example is for performing blow molding of a PET bottle, and for stretching a test tube-shaped preform P having one end opened to mold a container B such as soft drink. belongs to.

As shown in FIG. 1, in the apparatus 1 of this example, two preforms P1 and P2 are received from the preform delivery station 2 at the left end of the figure, and the molded containers B1 and B2 are It is designed to be handed over from the take-up station 3 to the processing station (not shown) in the subsequent stage. A linear transport path is formed between the transfer station 2 and the take-out station 3, and the pre-stage heating station 5, the post-stage heating station 6, and the stretch molding machine 7 are arranged in this order along the transport direction of this transport path. Are arranged in. The preform P transported on the transport path is heated to a predetermined temperature in the pre-stage heating station 5, passes through the pre-form P, and the surface thereof is cooled. Thereafter, the pre-form P is suitable for stretch molding again in the post-stage heating station 6. It is heated to the desired temperature and the surface is cooled again. Next, it is stretch-molded in the stretch-molding machine 7 to be molded into the container B.

The transport mechanism for transporting the preform P along the transport path comprises a first transport section 8 for transporting the preform P received from the preform delivery station 2 to the entrance of the stretch molding machine 7, and It is composed of a second transfer section 9 that receives the preform P from the transfer section 8 and performs molding in the stretch molding machine 7, and a third transfer section 11 that transfers the molded container B to the take-out station 3. There is.

With reference to FIGS. 1 and 2, the structure of the first carrying section 8 of this embodiment will be described. The carrying section 8 includes a beam 81 arranged along a carrying line, a plurality of preform carrying tools 82 arranged on the upper surface of the beam 81, and a carrying mechanism for moving the beam 81 back and forth along the carrying direction. 83, an elevating mechanism 84 for elevating the beam 81, and a plurality of preform holding mechanisms 85 arranged along the transfer line.

A plurality of transfer tools 82 arranged on the upper surface of the beam 81 are arranged at a constant interval L. Each transfer tool 8
Reference numeral 2 denotes a rod 821 rotatably supported with respect to the beam 81 and a preform carrying surface 8 formed on the upper end of the rod 821.
22 and an insertion rod 823 extending vertically from the center of the carrying surface 822. The beam transfer mechanism 83 has a support portion 831 that supports the beam 81. The support portion 831 is supported by a roller 832 so as to be movable forward and backward in the transport direction by a beam elevating mechanism 84. There is. Further, the beam support portion 831 is
One end thereof is connected to a link mechanism 833 that swings back and forth in the transport direction via a link mechanism (not shown). By swinging by this link mechanism 833, the beam support portion 831 moves back and forth in the transport direction. It is possible to move at a constant pitch. In this example, it is possible to move at a constant feed pitch of 2L.

The beam raising / lowering mechanism 84 comprises the above-mentioned beam supporting portion 831 and a raising / lowering guide 841 which supports the beam supporting portion 831 so as to be capable of moving up and down with respect to the apparatus mount 1A via a roller 832. . The beam support portion 831 is
The link mechanism 841 is configured to move up and down with a constant width. In this example, the beam transfer and the lifting operation are performed by a driving force from the same driving source via the link mechanism. As such a link mechanism, various structures can be used, and since it is a known technique to those skilled in the art, the details thereof will be omitted in this specification.

Here, in this example, the lower end of the rod 821 constituting the transfer tool 82 is connected to the motor 825 attached to the beam supporting portion 831 via the pulley and the belt mechanism 824. , With this motor,
It is designed to rotate about its axis.

Next, as shown in FIG. 2, four rollers 851, 852, 853 and 8 centered on the circumference of the axis at the position corresponding to each transfer tool 82.
Preform holding mechanisms 85 with 54 are arranged respectively. The rollers 851 and 852 on one side are attached to the apparatus mount 1A so as to be movable in a direction orthogonal to the transport direction.
The roller 851 is a drive roller connected to the motor 856 via a belt / pulley mechanism 855. The motor 856 is also supported so as to move integrally with the rollers 851 and 852. The other roller 853, 854
Also, similarly, it is mounted in a movable state in a direction orthogonal to the transport direction. In the present example, as shown in the figure, when the rollers on both sides are brought close to each other, the preform P is sandwiched between them so that the driving roller 85 can be formed in this state.
When 1 is rotated, the preform P held between the rollers can be rotated around its axis. It goes without saying that the number of rotations of the rollers substantially matches the speed at which the preform P rotates by the rotation of the transfer tool 82.

Here, in this example, the opening and closing operations of these left and right rollers are also controlled by the beam 8 through a link mechanism or the like.
It is configured to be performed by the same drive source 80 as 1.

The transfer operation of the preform P in the first transport section 8 of the present embodiment thus constructed will be described with reference to FIGS. 3 and 4. Each transfer tool 82 on the beam 81
It is assumed to be at the initial position 82A on the front side in the transport direction A shown in FIG. In this state, the roller group of the holding mechanism 85 is in a closed state, and therefore, as shown in FIG. 3 (B), the preform P is sandwiched (time point T0 in FIG. 4). From this state, first, the elevating mechanism 84 descends to the lower second position 82B (time T in FIG. 4).
1). The preform P is held by the holding mechanism 85 and held in a rotated state. By this descent, the transfer tool 8
The second insertion rod 823 comes out of the mouth of the preform P.

Next, the beam 81 is retracted backward by 2L by the beam transfer mechanism 83. As a result, the holder 82 reaches the retracted third position 82C (time T2 in FIG. 4). Next, the beam 81 is raised by the beam elevating mechanism 84 and reaches the retracted position 82D. here,
The retracted position 82D is a position two pitches behind the holder 82 with respect to the initial position 82A, and in this position, the preform P is held by the holding mechanism. Therefore, when the beam 81 rises, the insertion rod 823 of the transfer tool 82 is inserted through the mouth of the preform P, and the preform P is supported on the carrying surface 822 of the transfer tool (at the time of FIG. 4). T3). After this, as shown in FIG. 3C, a roller group composed of three or more rollers (four in this example) per block of the holding mechanism 85 opens left and right (time point T4 in FIG. 4). . As a result, the preform P is supported only by the transfer tool 82. After this, the beam transfer mechanism 83
The transfer tool 82 is again advanced to its initial position 82A (time T5 in FIG. 4). Here, the rod 8 of the transfer tool 82
Since 21 is always rotating, the preform P supported there is also always rotated and conveyed. After that, the rollers of the holding mechanism 85 are closed again to form a state in which the preform P is held (time T6 in FIG. 4).

Thus, in this example, the beam 81
The preforms P are conveyed at a constant feed pitch 2L by the transfer tools 82 that move together with the transfer tools 82.

After one carrying operation, as shown in FIG. 4, the preform carried into the stretch molding machine 7 is molded (from time T7 to T).
8). The stretch molding machine 7 of this example may be the same as the one generally used, and its molding operation is also the same, so that the description of its structure and operation will be omitted.

After that, the same cycle is repeated to carry the preform conveyance and molding operations.

Next, in the present example, the preform P is received from the first conveying section 8 having the above-mentioned structure, and the stretch molding machine 7 is provided.
The second transfer section 9 that is carried into the container is also basically the first transfer section 8
Is configured similarly to. However, as can be seen from FIG. 1, the second transport section 9 is provided with a pair of transfer tools 91, 92, and these retracted positions 91A,
The distance L at 92A is different from the distance L2 inside the molding machine. In order to make the feed pitch different in this way, the feed pitch may be set differently by using a cam and a link mechanism. Alternatively,
The feed pitch may be made different by forcibly bringing the plurality of transfer tools slidable via compression springs into close contact with each other or separating them. Various types of such mechanisms can be adopted. This second transport section 9
Then, the configuration is the same as that of each of the transfer tools in the first transfer unit 8 except that a pair of transfer tools are provided as described above, the feed pitches thereof are different, and the preform rotation mechanism is not provided.

On the other hand, the third transfer section 11 is also basically the first
Is the same as the transport unit 8 of FIG.
The molding machine 7 transfers two moldings B1 and B2 from the molding machine 7 and carries them out to a processing station (not shown) on the subsequent stage. The configuration of this transport unit is also the same as that of the first transport unit 8 except that the feed pitch is different and that a rotation mechanism for the molded product is not provided.

In the transfer mechanism of the blow molding apparatus 1 of the present embodiment thus configured, the transfer of the preform is realized by repeatedly moving the plurality of transfer tools 82 supported by the beam 81 back and forth and up and down. is doing. Therefore, as compared with the conventional transport mechanism in which the moving tool itself moves along the transport line, the configuration can be simplified and the manufacturing cost can be reduced.

Further, since the transfer tool itself rotates,
While being conveyed by the transfer tool, the preform is rotated by the transfer tool, and while the transfer tool is retracted, the preform is rotated by the holding mechanism composed of rollers. Therefore, the heating stations 5, 6
The preform is continuously rotated while being conveyed. Therefore, the preform can be heated uniformly.

Further, in this embodiment, the beam elevating mechanism, the beam transferring mechanism and the holding mechanism are moved by the driving force of the same driving source by utilizing the cam, the link mechanism and the like. Therefore, there is also an advantage that the device can be made compact. In addition to this, in this example, the second and third conveyors for conveying the preforms and the molded products at different feed pitches are also driven by the driving force from the same driving source. It can be made compact.

Next, in the transport mechanism of this example, each transfer tool 82 only moves back and forth and up and down in a fixed place. Therefore, it is possible to easily form a configuration in which the transfer tool is partially prevented from rotating and the preform transferred by the transfer tool is transferred in a non-rotating state. Therefore, for example, if only one or a plurality of transfer tools 82 located immediately before the stretch molding machine 7 in the post-stage heating station 6 are not rotated, only the desired portion of the preform P transported here is not rotated. Can be partially heated or cooled. When the temperature change is imparted to the preform immediately before stretch molding in this way, the amount of stretching of each portion during stretch molding can be controlled, and the wall thickness of the molded product can be adjusted.
As a result, there is an advantage that it is possible to avoid the adverse effect that the portion having a large amount of stretching becomes too thin.

As a mechanism for partially heating and cooling in this way, a structure in which air set in a predetermined temperature range is blown to a target portion of the preform can be adopted. Instead of this, it is also possible to adopt a configuration in which the heat transfer piece set to a predetermined temperature is brought into contact with the target portion of the preform.

In order to properly perform the stretch forming, immediately before the stretch forming in the latter heating station 6, air set to a predetermined temperature is blown to the conveyed preform to form the preform. It is preferable to set a uniform temperature state.

[0038]

As described above, in the blow molding apparatus of the present invention, each transfer tool constituting the preform transfer mechanism only moves by the feed pitch, and The retaining mechanism of the reform may perform retaining and opening operations of the preform at a fixed position. Therefore, the transport mechanism can be made extremely simple and inexpensive as compared with the conventional configuration in which each transfer tool circulates along the transport line.

Further, in the present invention, since the preform is rotated around its axis by the respective transfer tools and the respective holding mechanisms, the preform can be uniformly heated as a whole.

Further, in the present invention, the feed pitch of the preform on the conveying path passing through the heating station and the feed pitch of the preform in the stretch molding machine are set to be different, and such a difference in the feed pitch is set. ,
It is realized by a driving force from the same driving source through a rack and a pinion mechanism, a power transmission mechanism such as a cam and a link mechanism, and the like. Therefore, the device can be made compact.

On the other hand, the present invention is characterized in that the temperature adjusting means for adjusting the heating temperature of the preform is arranged in the conveying path immediately before the stretch molding machine. For example, a temperature equalizing means for adjusting the preform to a uniform temperature suitable for the stretch molding temperature is arranged by blowing air set in a predetermined temperature range over the entire preform. . By doing so, the preform can be accurately adjusted so that the temperature is optimum for the stretch forming just before the stretch forming. Further, after the preform is adjusted to a uniform temperature, by blowing air set in a predetermined temperature range on a part or by contacting a heat transfer piece set in a predetermined temperature to the preform, On the other hand, the temperature change is partially applied. This has the advantage that the amount of stretching of each part of the preform during stretching can be adjusted.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a configuration of a blow molding apparatus that is an embodiment of the present invention.

2 is a schematic cross-sectional view of the device of FIG.

3A and 3B are diagrams for explaining a transfer operation in the apparatus of FIG. 1, and FIG. 3A is an explanatory diagram showing movement of each transfer tool;
(B) And (C) is explanatory drawing which shows operation | movement of a preform holding mechanism.

FIG. 4 is a time chart showing the operation of the apparatus of FIG.

[Explanation of symbols]

1. Blow molding device 3 ... Take-out station 5 ... Front heating station 6 ... Post-heating station 7 ... Stretch molding machine 8, 9, 11 ... Transport mechanism 81 ... Beam 82 ... Transfer tool 82A ... initial position of transfer tool 82D ... Retracted position of the transfer tool 83 ... Transfer mechanism 84 ... Lifting mechanism P (P1, 2) ... preform B (B1, B2) ... Container (molded product)

Claims (12)

(57) [Claims] 1. A heating means for heating a preform having an open end, and a stretching for biaxially stretching the heated preform into a molded article of a predetermined shape. Forming means, take-out means for taking out the formed article obtained through the stretch forming means, and conveying the preform toward the stretch forming means through the heating means, and the obtained formed article is subjected to the stretching. And a transfer means for transferring the transfer means from the molding means to the take-out means, wherein the transfer means are arranged at a constant interval and can be inserted into the open ends of the preforms, and each transfer tool has an initial position. A transfer mechanism for lowering the position and moving it to the retracted position by retracting it in the direction opposite to the transport direction and then raising it again, and advancing it from the retracted position to the initial position; While holding the preform until moving from the initial position to the retracted position, the preform has a holding mechanism for opening and delivering the preform to the transfer tool that has reached the retracted position, and the preform has a predetermined shape. A blow molding device characterized by being intermittently conveyed at a feed pitch. 2. The holding mechanism according to claim 1, wherein the holding mechanism includes a plurality of rollers and a roller moving unit that holds and releases the preform by relatively approaching and separating the rollers. Blow molding equipment. 3. The blow molding apparatus according to claim 1, further comprising a rotation driving unit that rotates the transfer tool that moves in a heating region of the heating unit. 4. The holding mechanism for holding a preform in a heating region of the heating means according to claim 2 or 3, further comprising a roller rotating means for rotating at least one of the rollers. Characteristic blow molding equipment. 5. The feed pitch of the preform in a conveying path passing through the heating means, and the preform in a conveying path passing at least the stretch forming means according to any one of claims 1 to 4. The blow molding device is characterized by having a different feed pitch. 6. The same drive source as set forth in claim 5,
By taking it out through a power transmission mechanism such as a rack and pinion mechanism, a cam and a link mechanism, or by forcibly adhering or separating a plurality of transfer tools slidable via compression springs, A blow molding apparatus, characterized in that the preform feeding operation at the different pitch is performed. 7. The temperature adjusting device according to claim 1, wherein the conveying path immediately before the stretch forming device has a temperature adjusting device capable of adjusting a heating temperature of the preform. Characteristic blow molding equipment. 8. The temperature adjusting means according to claim 7, wherein the temperature adjusting means blows air containing a humidity set in a predetermined temperature range over the entire preform, so that the inside and outside of the preform are suitable for the stretch forming temperature. A blow molding apparatus comprising a temperature equalizing means for adjusting the temperature distribution so as to obtain a uniform temperature distribution. 9. The preform according to claim 8, wherein the temperature adjusting means blows air containing a humidity set in a predetermined temperature range onto a part of the preform after the preform is adjusted to a uniform temperature. A blow molding apparatus characterized in that it is provided with a temperature change imparting means for partially imparting a temperature change to the. 10. The temperature change imparting means according to claim 9, wherein the temperature change is locally imparted to the preform by bringing a heat transfer piece set at a predetermined temperature into contact with the preform. The blow molding apparatus is characterized in that 11. The temperature adjusting means according to claim 7, wherein the temperature adjusting means blows air containing a humidity set in a predetermined temperature range onto a part of the preform, thereby partially changing the temperature of the preform. A blow molding device, characterized in that the blow molding device is provided. 12. The temperature adjusting device according to claim 7, wherein the heat transfer piece set to a predetermined temperature is brought into contact with the preform to partially change the temperature of the preform. The blow molding apparatus is configured such that the conveying means conveys the preform in the conveying path passing through the temperature adjusting means without rotating the preform.