HK1015731A - Biaxial stretch - moding apparatus - Google Patents

Description

Biaxial stretch-forming machine

Technical Field

The present invention relates to a biaxial stretch-forming machine suitable for forming PET bottles and the like. More particularly, the present invention relates to a biaxial stretch-forming machine which can be configured in a compact and small size.

Background

Molded articles such as PET bottles can be obtained by heating and then subjecting a preform formed by injection molding to stretch molding using a biaxial stretching mold. A biaxial stretch-forming machine for this purpose can carry out a forming operation by sequentially carrying preforms at a constant carrying pitch through respective processing sections arranged along a carrying path. An example of a biaxial stretch-forming machine of this type is disclosed in, for example, japanese patent publication No. 1-17855.

In the biaxial stretching machine disclosed in the above publication, the preform conveying line is formed in a rectangular shape, and rectangular parallelepiped conveying members (preform carriers) are arranged on the conveying line, and they can be sequentially conveyed at a constant conveying pitch. Each of the transport members has an insertion core insertable into a mouth of the preform, and the preform can be transported in a state where the mouth is inserted into the insertion core. After receiving the preform, the conveying members are conveyed via the heating section and the stretch forming section, and after the molded product is transferred to the collecting section, the operation of returning the molded product to the preform supplying section is repeated in an empty state.

In a biaxial stretching machine which carries a preform carrier for supporting a preform along such a closed conveying line and performs a biaxial stretching operation, the following problems need to be solved.

1, after the preform carrier passes through the heating section and the stretch forming section, the molded article is taken away, and thereafter, the preform carrier is returned again to the preform supplying section. The stretch-forming section has a forming die that can be opened and closed in a direction perpendicular to the conveying line, and it is necessary to secure a space having a size equal to the stroke of the forming dies on both sides. Therefore, the width of the stretch-formed part is very large compared with other parts in the biaxial stretch-forming machine. In the prior art, the conveyance path is a flat conveyance path formed at the same height position, and a portion of the conveyance path from the stretch forming portion to the preform supply portion is a path bypassing the outside of the wide stretch forming portion. As a result, the biaxial stretch-forming machine has a disadvantage of increasing in size. Further, the entire length of the conveying path is increased, and therefore, the time for circulating the preform carrier tray along the conveying path once is also increased, which disadvantageously decreases the processing speed.

And 2. the preform carrier is transported via the preform supplying part, and the preform is mounted on the carrier by inserting the mouth of the preform into the insert core of the preform carrier from above. If the mouth of the preform is not inserted into the insert with certainty, the latter stage of the process cannot be properly performed. However, the reason for the incomplete insertion is only that the insertion is insufficient or that the mouth of the preform is deformed and cannot be inserted. No mechanism for recognizing and appropriately processing the same has been proposed in the prior art.

And 3. in the stretch forming part, a blowing air blowing core and a stretching rod are inserted into the mouth of the preform supported by the preform carrier, and biaxial stretch forming of the preform is performed. It would be advantageous if the movement of these cores and extension rods could be performed more efficiently than with existing mechanisms, since the efficiency of the process could be increased.

Disclosure of the invention

In view of the above problems, an object of the present invention is to provide a biaxial stretch-forming machine which is compact and compact by making a conveyance path the shortest distance.

It is another object of the present invention to provide a biaxial stretching molding machine capable of reliably recognizing deformation and defective insertion of a preform supplied from a preform supply section to a preform carrier tray.

It is another object of the present invention to provide a biaxial stretch-forming machine capable of efficiently moving a blowing air blowing inlet core and a stretching rod in a stretch-forming section.

In order to achieve the above object, the present invention provides a biaxial stretching molding machine comprising a preform supplying section, a preform heating section, a biaxial stretching molding section for biaxially stretching a heated preform, a collecting section for collecting a molded article, a closed type conveying path sequentially passing through these sections, and a preform carrier tray conveyed along the conveying path, wherein the conveying path of the preform carrier tray is three-dimensionally configured to minimize the length of the conveying path, to achieve a compact size and to improve the processing efficiency.

That is, in the present invention, the conveyance path includes a1 st conveyance path portion and a2 nd conveyance path portion, the 1 st conveyance path portion conveys a preform carrier holding a preform by the preform heating section and the biaxial stretching forming section, and the 2 nd conveyance path portion conveys the preform carrier, from which a molded article is collected, to the preform supply section while bypassing a lower side or an upper side of the biaxial stretching forming section. By forming the conveyance path portion on the lower side or the upper side of the biaxial stretching molding part in this way, the entire length of the conveyance path can be shortened as compared with a flat conveyance path as in the related art. In general, it is preferable to form a part of the conveying path passing through the lower side of the biaxial stretch-forming part.

Here, in the case of forming the conveyance path portion passing through the lower side of the biaxial stretching molding section, it is preferable to arrange a molded article extracting device for extracting the molded article having the insertion core of the preform carrier tray inserted into the opening from the tray by the operation of lowering the preform carrier tray from the collection section to the conveyance path portion located on the lower side. Such a drawing device can be used only as a simple mechanism for holding the mouth of a molded article. That is, if the mouth of the molded article is gripped from both sides by the drawing device, the preform carrier tray itself is lowered, and the molded article can be automatically drawn from the tray.

In the biaxial stretching machine of the present invention, the preform carriers are also conveyed in a state of being aligned in a row in the conveying direction through the heating section of the 1 st conveyance path portion, and the conveying pitch of the preform carriers in the heating section is set to the length of 1 preform carrier in the conveying direction. In this case, it is desirable to arrange the conveying means so that the conveying pitch of each preform carrier tray transferred from the heating section to the biaxial stretching forming section is larger than the conveying pitch of the preform carrier tray conveyed through the heating section. Thus, a large-diameter molded article can be formed in the biaxial stretching molding section. In addition, the preform can be conveyed at a narrow conveying pitch in the heating section. Therefore, the arrangement density of the preforms in the heating section can be increased, the heating efficiency can be improved, the required conveying path can be shortened, and the apparatus can be made compact.

On the other hand, the biaxial stretching molding machine of the present invention has a driving device for independently performing the insertion operation of the blowing air blowing core and the stretching rod inserted from the preform opening. In this configuration, the stroke of movement (generally, elevation) of the blowing air blowing core can be significantly shortened, and the time required for the movement can be shortened, thereby improving the treatment efficiency.

In the biaxial stretching molding machine of the present invention, a pushing device for pushing the preform into the insert core is provided between the preform supplying section and the heating section. The preform can be reliably supported by the pushing device on the preform carrier.

Here, it is desirable that the pushing device has a position sensor for detecting the height position of the preform after pushing. Since the preform with the deformed mouth portion cannot be pushed in, if the height position of the preform after the pushing in is detected, the deformed defective preform can be surely detected.

Brief description of the drawings

Fig. 1 is a schematic view showing the overall structure of a biaxial stretch-forming machine using the present invention.

Fig. 2 is a side view of a biaxial stretch-forming machine according to the present invention.

Fig. 3 is a plan view of the biaxial stretch-forming machine of fig. 2.

Fig. 4 is a cross-sectional structural view of a biaxial stretch molding part of the biaxial stretch molding machine of fig. 2.

Fig. 5 is a perspective view of a preform carrier carriage in the biaxial stretch-forming machine of fig. 2.

Fig. 6 is an explanatory view showing a conveying mechanism for feeding the heated preform to the biaxial stretch-forming section in the biaxial stretch-forming machine of fig. 2.

Best mode for carrying out the invention

An embodiment using a biaxial stretch-forming machine according to the present invention will be described below with reference to the drawings.

Fig. 1 is a schematic view showing the overall structure of the biaxial stretch-forming machine of the present embodiment. Fig. 2 to 4 are a side view, a plan view, and a cross-sectional view of a biaxial stretch-forming part of the biaxial stretch-forming machine according to the present example. Fig. 5 is a perspective view of the preform loading tray, and fig. 6 is an explanatory view showing a conveying mechanism for feeding the heated preform into the biaxial stretching molding section.

The following description is made with reference to fig. 1 to 4. The biaxial stretch molding machine 1 of the present embodiment includes a preform supply section 2 for supplying a preform P, a preform heating section 3, a biaxial stretch molding section 4 for biaxially stretch-molding the heated preform P1, a recovery section 5 for recovering a molded article P2, a closed conveyance path 6 passing through these sections in sequence, and a plurality of preform carrier trays 7 conveyed along the conveyance path 6.

The transfer path 6 is of a rectangular closed shape as shown by a thick line in fig. 3, and the transfer direction of the preform carrier tray 7 is shown by an arrow. In this example, the conveyance path 6 has a1 st conveyance path portion 62 (a route from point a to point B in fig. 3) and a2 nd conveyance path portion 64 (a route from point C to point D in fig. 1 and 3). In the first conveyance path part 62, a preform carrier tray 7 supporting a preform P is conveyed through a preform heating section 3 and a biaxial stretching forming section 4; the preform carrier tray 7 from which the molded product P2 has been collected is conveyed to the preform supplying section 2 through the lower side of the biaxial stretching molding section 4 in the 2 nd conveyance path section 64. As shown in fig. 1 and 4, the 2 nd conveyance path portion 64 is structured to pass through a lower side position of the blow mold clamping mechanism 41 of the biaxial stretching forming section 4.

Each of the carryway segments 62, 64 is a horizontal carryway. Therefore, the conveyance path portion of these conveyance path portions on the preform supply side becomes the ascending path portion 61 from the 2 nd conveyance path portion 64 on the lower side to the 1 st conveyance path portion 62 on the upper side (a path from point D to point a in fig. 1 and 3). In contrast, the conveyance path portion on the molded article collection side becomes a descent path portion 63 (a path from point B to point C in fig. 1 and 3) from the 1 st conveyance path portion 62 on the upper side to the 2 nd conveyance path portion 64 on the lower side.

As described above, in the biaxial stretch-forming machine 1 of this example, the preform conveying path 6 is not formed in a planar form but in a three-dimensional form. Therefore, the mechanical space, particularly the width dimension thereof can be significantly reduced as compared with the conventional case where the preform carrying path is formed so as to pass around the blow mold clamping mechanism 41 of the biaxial stretching molding section 4 in a planar manner. Therefore, the biaxial stretch-forming machine can be made compact. In addition, since the overall length of the preform transfer path can be significantly reduced, the cycle time for circulating the preform carrier tray 7 once can be significantly reduced, thereby improving the processing efficiency.

Here, as shown in fig. 5, the preform carrier 7 is composed of a rectangular main body 71, a rotating shaft 72 vertically and rotatably penetrating the main body, a preform insert core 73 coaxially formed on the upper end surface of the rotating shaft 72, and a gear 74 having an overhang portion formed on the lower end side of the rotating shaft 72. A through hole 75 is formed in the center of the rotation shaft 72 and the insertion core 73. A blowing air inlet core can be inserted below the through hole 75 as described later. Further, an extension rod can be inserted into the upper preform P1 through the through hole 75.

The preforms P are fed onto the preform carrier tray 7 from the side of the preform feeding portion 2 to the point D. That is, the mouth of the preform P is held by a rotary clamp 22 rotatable about an axis 21, and the preform P is on standby with the mouth facing upward. Subsequently, when the gripper 22 rotates 180 degrees around the axis 21, the gripped preform P is inserted with its mouth facing downwards, right into the insertion core 73 of the preform carrier tray 7 waiting at the point D.

Thus, the preform carrier tray 7 holding the preforms P is moved in the Y-axis direction by the biaxial transfer mechanism 61A, and is simultaneously raised in the Z-axis direction to reach the point a. The preform carrier tray 7 reached to the point a is horizontally pushed out in the X-axis direction by the push rod 61B to be transferred to the 1 st conveyance path portion 62 by the two-axis conveyance mechanism 61A.

The 1 st transfer passage section 62 has a pair of rails 62a, 62b for sliding the rectangular body 71 of the preform carrier tray 7. When the carriages 7 are pushed out one by the above-mentioned push rod 61B, the carriages 7 placed on the rails are intermittently moved along the conveyance path portion 62. That is, in the conveyance path portion 62, a conveyance pitch is defined in accordance with the length of the carriage 7 in the conveyance direction, and the carriages 7 aligned in a row at the conveyance pitch are conveyed intermittently as a whole.

At a position near the point D of the 1 st transfer path portion 62, a pushing mechanism 8 for pushing the preform P downward is disposed. The pushing mechanism 8 is used to push the preform P into the insert 73 of the carrier 7 again. The pushing mechanism 8 further includes a position sensor 8a, and the position sensor 8a detects the height of the preform P after pushing. The preform P is conveyed to the heating section 3 of the next stage by the pushing mechanism 8 in a state where the preform P is surely inserted into the pallet 7. In the case where the preform P cannot be pushed in by the pushing mechanism 8, the height of the preform P is higher than that in the normal state, and therefore, the height can be detected by a position sensor. In this case, it can be displayed or reported that the preform P belongs to a preform having a defect such as deformation of the mouth. Therefore, the insertion failure of the preform P can be eliminated, and a defective preform can be detected.

Heaters for heating preforms are arranged on one side of the heating section 3 along the conveyance path 62. The preform P is conveyed in the heating section 3 while being rotated by a turning mechanism 62A, and the turning mechanism 62A is constituted by a drive pulley, a driven pulley, and a timing belt interposed therebetween. That is, the timing belt is engaged with the gear 74 of the carrier 7, and when the gear 74 is rotated, the carrier rotating shaft 72 integrally attached with the gear 74 is rotated, and the preform P inserted into the insert core 73 on the upper end surface thereof is also rotated.

The preform P1 heated while being rotated by the heating section 3 is cooled for a certain period of time after passing through the heating section 3, and is brought into a temperature state suitable for molding. Then, the sheet is conveyed into the biaxial stretch-forming section 4. In this example, a conveying mechanism 9 is provided, and the conveying mechanism 9 is used to feed the carriers 7 supporting the heated preforms P1 one by one to the biaxial stretching forming section. The conveying mechanism 9 is used to feed the biaxial stretching forming section 4 one by one at a conveying pitch larger than that of the heating section 3.

As shown in fig. 6, the carrying mechanism 9 is provided with a pair of grippers 91, 92 at an interval of a carrying pitch L2 toward the carrying direction. These grippers are integrally reciprocated in the conveying direction at a conveying pitch L2. The carriage 7 carried to the point a1 at the pitch L1 through the heating section 3 is supported by the clamp 92. In this state, the front clamp 91 is located at the forming position a2 of the biaxial stretch-forming portion 4.

After the biaxial stretching molding is completed, the grippers 91 and 92 are moved in the carrying direction at a carrying pitch L2. As a result, as shown by the solid line in fig. 6, the holder 7 holding the rear clamp 92 reaches the biaxial stretching position a2, and the front clamp 91 holding the holder holding the molded article reaches the point B. The conveying mechanism 9 repeatedly performs such reciprocating operations to convey the carriers 7 conveyed at the conveying pitch L1 to the biaxial stretching molding unit 4 at a conveying pitch L2 larger than that of the carriers.

Since the conveying pitch of the biaxial stretch-forming section 4 is increased in this way, a container having a large tube diameter can be formed regardless of the conveying pitch of the heating section 3. On the contrary, by reducing the conveying pitch of the heating section 3, the length of the heating section 3 in the conveying direction can be shortened, the arrangement density of the preforms P in the heating section can be increased, and the heating efficiency can be improved. In this way, since the length of the heating section in the conveying direction can be shortened, the size of the biaxial stretch molding machine can be reduced.

The biaxial stretching molding section 4 of this example is provided with a 1-component mold 42, a mold clamping mechanism 41 of the mold, a blowing air blowing core 43 inserted from an opening of a preform, an extension rod 44 inserted from an opening of the same preform, and a driving mechanism 45 for independently performing the insertion operation of the blowing air blowing core 43 and the extension rod 44.

When the preform P is conveyed to the point a2 at the time of molding, the pair of left and right molding dies 42 are closed by the mold closing mechanism 41. Thereafter, the blowing air blowing core 43 is raised and connected to the through hole 75 of the tray 7, and air starts to be blown into the preform P. At the same time, the extension rod 44 is raised and inserted into the preform through the bracket through hole 75. Biaxial stretching was performed by blowing air and inserting an extension bar 44. In this example, the blowing air blowing core 43 having a small lifting stroke and the extension rod 44 having a large lifting stroke can be driven separately. Therefore, compared to the case where the blown air inlet core 43 is moved up and down together with the extension rod 44 by a large stroke as in the conventional art, the time required for moving up and down the blown air inlet core 43 can be significantly reduced, and the processing efficiency can be improved.

Next, the molded article P2 obtained by the biaxial stretching molding described above is conveyed to the point B by the conveying mechanism 9. At this point B, the carriage 7 is transferred to the biaxial transport mechanism 63A.

When the carrier 7 is transferred to the biaxial transport mechanism 63A, the neck portion of the molded product P2 on the carrier is gripped by the rotating gripper 5A of the molded product collecting section 5. In this state, the two-axis conveying mechanism 63A lowers (moves in the Z-axis direction) the carriage 7. As a result, the insert 73 on the side of the bracket 7 is pulled out from the opening of the molded product P2. Thereafter, the rotary pincer 5A is rotated to collect the molded product P2. Thus, in this example, the drawing mechanism is configured to draw the molded product P2 out of the tray 7 side by the lowering of the biaxial transfer mechanism 63A. Therefore, the molded product P2 can be recovered by a simple mechanism.

The two-axis conveying mechanism 63A conveys the empty carriage 7 to the starting point C of the 2 nd conveying path portion 64 by descending (conveying in the Y-axis direction). When the carriage 7 reaches the point C, the carriage is pushed out in the X-axis direction from the side of the biaxial transport mechanism 63A by the push rod 63B, and enters the pair of right and left transport belts 64a, 64B constituting the 2 nd transport path portion 64. The carrier 7 is conveyed to the preform supplying section 2 side by these conveying belts through the lower side of the mold clamping mechanism 41 of the biaxial stretching molding section 4.

Thereafter, the carrier 7 is repeatedly moved in the conveyance path 6 in the same manner, and biaxial stretching of the preform is performed. (other embodiments)

In the above example, the biaxial stretching molding section 4 is provided with 1-component molding die, i.e., 1-piece molding die. It is also possible to replace it with a structure of 2. In this case, a conveyance mechanism that conveys 2 carriers 7 at a time may be employed instead of the conveyance mechanism 9. In this case, the interval between the 2 carriages may be increased in conjunction with the conveyance operation. Possibility of industrial utilization

As described above, in the biaxial stretching machine of the present invention, the conveyance path of the preform carrier tray is three-dimensionally formed, and therefore, the entire biaxial stretching machine can be made compact and small.

In the present invention, the molded article is pulled out from the preform carrier tray by the operation of lowering the preform carrier tray along the three-dimensionally configured conveyance path, so that the molded article pulling-out mechanism can be formed in a simple configuration.

Since the conveying pitch at the time of transfer to the biaxial stretching forming section can be increased with respect to the conveying pitch of the preform heating section, the thick-tube formed article can be formed, and the arrangement density of the preforms in the heating section can be increased, so that the heating efficiency can be improved.

In addition, since the biaxial stretch forming section can independently drive the blowing air inlet core and the extension rod, the blowing air inlet core can be efficiently driven compared to a mechanism that integrally drives them.

On the other hand, in the present invention, there is a mechanism for positively inserting the preform into the preform carrier tray, and a position sensor is provided at the pushing mechanism. According to this configuration, a defective preform in which the mouth portion is deformed can be reliably identified.

Claims (8)

1. A biaxial stretching molding machine comprising a preform supplying section, a preform heating section, a biaxial stretching molding section for biaxially stretching a heated preform, a collecting section for collecting a molded article, a closed conveying path passing through these sections in this order, and a preform carrier tray conveyed along the conveying path; the method is characterized in that: the conveying path has a1 st conveying path portion and a2 nd conveying path portion, the 1 st conveying path portion conveys a preform carrier holding a preform through the preform heating section and the biaxial stretching forming section, and the 2 nd conveying path portion conveys the preform carrier, from which a molded article is collected, to the preform supplying section by bypassing a lower side or an upper side of the biaxial stretching forming section.

2. The biaxial stretch-forming machine according to claim 1, wherein: the 2 nd conveyance path portion is formed at a position lower than the 1 st conveyance path portion and passes under the mold clamping mechanism of the biaxial stretching molding section.

3. The biaxial stretch-forming machine according to claim 2, characterized in that: the transfer path is provided with a 3 rd transfer path portion for transferring the preform carrier tray to the 2 nd transfer path portion after descending the preform carrier tray received from the 1 st transfer path portion on the recovery portion side; further, a molded article extracting device is provided, which extracts a molded article from the preform carrier tray by the lowering operation of the preform carrier tray of the 3 rd conveyance path portion.

4. The biaxial stretch-forming machine according to any one of claims 1 to 3, wherein: the preform carriers are conveyed in a row in the conveying direction through a heating portion of the first conveying path portion 1, and the conveying pitch of the preform carriers in the heating portion is defined by the length of 1 preform carrier in the conveying direction.

5. The biaxial stretch-forming machine according to claim 4, wherein: a conveying device is provided for making the conveying pitch of each preform carrier transferred from the heating section to the biaxial stretching forming section larger than the conveying pitch of the preform carrier conveyed through the heating section.

6. The biaxial stretch-forming machine according to any one of claims 1 to 5, wherein: the biaxial stretching molding section is provided with a blowing air blowing inlet core inserted from the opening of the preform, an extension rod similarly inserted from the opening of the preform, and a driving device for independently performing the insertion operation of the blowing air blowing inlet core and the extension rod.

7. The biaxial stretch-forming machine according to any one of claims 1 to 6, wherein: a pushing device for pushing the preform into the preform carrier is disposed between the preform supplying section and the heating section.

8. The biaxial stretch-forming machine according to claim 7, wherein: the pushing device is provided with a position sensor for detecting the height position of the pushed preform, and a defective preform can be detected based on the detected height position.