JPS6217523B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves molding a parison with a bottle neck for manufacturing bottles by a blow molding method.
An injection mold having a plurality of molds, the mold having a nozzle-side plate fixed in position with respect to the injection molding machine and forming a generally cylindrical outer section of the parison on the fixed plate. An outer contouring mold is arranged, and a bottom contouring mold member forming the bottom of the parison is provided, each of which has a hot water distribution runner mounted on the fixed plate. A runner is formed that is connected to the system and is provided with a runner closing needle that is axially movable via a drive and that engages the runner and is movable relative to the injection molding machine. A core retaining plate is provided, to which is fixed a leg section of the core that enters the outer profiling mold, the core retaining plate extending perpendicularly to the axis of the outer profiling mold. A movable neck mold is provided, the neck mold having an inner contour forming an outer shape of a bottle neck portion with a thread and a neck ring having a diameter larger than the thread; The core is divided by a plane passing through the center axis of the parison, and the same neck mold is disposed on an intermediate plate, which is connected to the core holding plate in the opening/closing direction of the injection mold when the core is pulled out from the parison. The invention relates to a type in which at least one hydraulic drive is provided for the neck mold.

In known injection molds with multiple molds, the outer contour mold is formed by an inner casing inserted through holes in a common plate.
The net molds of the individual molds located next to each other are in this case arranged in strips each extending over a large number of individual molds arranged in a row, and these strips are arranged diagonally. Since they are guided along guide surfaces, these strips carry out not only a movement perpendicular to the axis of the individual mold, but also an axial movement. Injection molds of this type are usually made of 16 to 3
It is designed to be able to mold two parisons.

Also, the Federal Republic of Germany Patent Application Publication No.
Another injection mold disclosed in US Pat. No. 2,148,616 is configured as a combined injection mold and blow mold for a one-stage injection blow molding process. In this known injection mold, the outer profile mold of the injection molding station is located on a circumference about a rotation axis about which the two mold parts can be pivoted relative to each other. In this case, the mold surfaces are each formed in an inner casing arranged on a common plate, in which the inner casings for the blow molds are arranged alternately. In this case, in order to form the outer contour of the neck part of the parison, a divided neck mold is provided, which neck mold is guided along an oblique guide surface provided on the intermediate plate. They are each movable in the plane of the supporting surface via an associated hydraulic drive. In this known injection mold, the neck mold is limited by the structure and function of the mold for each injection molding station, but the guides are all formed in one intermediate plate.

For parisons used to manufacture containers, especially bottles, by blow molding, it is strongly desired that the wall thickness be uniform, that no burrs form in the closed area of the bottle neck, and that the weight be constant. . Furthermore, such molds are designed for injection molding with polyethylene terephthalate (PETP). PETP is a material that crystallizes at temperatures between 80℃ and 250℃, so PETP is injected at temperatures above 2550℃ and cooled at high speed to temperatures below 80℃ to ensure the amorphous structure of the parison. must be done. This results in significant thermal loads on the mold parts during operation and different thermal expansions in the individual mold plates. This thermal expansion is
Careful consideration must be taken in the construction of the injection mold to ensure the coaxiality of all components at operating temperatures. As a result, the manufacturing costs of the known injection molds mentioned above are considerably high.

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide an injection mold with a large number of molds, in which the thermal problems can be solved in a simple manner and which can be manufactured easily.

In order to solve this problem, in the configuration of the present invention,
In an injection mold of the type mentioned at the outset, the outer contour mold is designed as an inner casing, and the circumferential surface of the hole provided in the inner casing is
forming a mold surface defining the outer contour of the parison, each inner casing being surrounded by a separate outer casing, which is screwed on the end side to a fixed plate; As a result, the inner casing is also fixed relative to a fixed position plate, and a separate neck mold is assigned to each inner casing, each neck mold having a conical inner circumferential surface of the inner casing. a conical outer circumferential surface that cooperates with the core and is coaxial with the bottle neck, and a conical inner circumferential surface that cooperates with the conical outer circumferential surface of the core and is also coaxial with the bottle neck; Each neck mold is supported in its own guide which extends perpendicularly to the opening direction of the injection mold, and each of the neck molds which are located adjacent to each other is A common hydraulic drive is provided for opening and closing the mold.

In an injection mold according to the invention, the outer contouring mold is designed as an inner casing, which inner casings are each surrounded by a separate outer casing which is screwed on the end face to a stationary plate. In contrast to known arrangements in which the inner casing is arranged in holes in a common plate,
The individual molds are physically and therefore thermally separated from each other. This means that each individual mold can independently follow the expansion of the stationary plate to which all the individual molds are fixed. In this case, the centering of the individual molds is e.g.
This takes place via a centering addition that engages in a corresponding recess of the bottom contouring mold part which is arranged in a stationary plate.

Due to the fact that each separate neck mold is assigned to the inner housing, the neck molds of the individual molds are also physically and therefore thermally separated from one another.

Each neck mold has a conical outer circumferential surface cooperating with the conical inner circumferential surface of the inner casing and coaxial with the bottle neck, and a conical outer circumferential surface cooperating with the conical outer circumferential surface of the core and also coaxial with the bottle neck. Due to the conical inner periphery, each neck mold is individually centered in its own inner casing via the conical outer periphery, so that the inner casing and the bottom molding The entire outer contour defined by the part and the neck mold is centered independently in each individual mold and is also thermally separated from the adjacent mold in this case.

In the injection mold according to the invention, each neck mold is each supported on its own guide which extends perpendicularly to the opening direction of the injection mold.
With this configuration, the netsuku mold is given pure lateral movement by the guide, so
Centering need only take place on the outer casing and on the inner casing. Therefore,
The double adjustment that necessarily occurs in the movable parts of the mold when the neck mold is guided obliquely can be avoided.

Furthermore, in the injection mold according to the present invention, a common hydraulic drive device is provided for each of the plurality of neck molds located adjacent to each other, for opening and closing these neck molds. This makes it possible to operate multiple neck molds together, even though the neck molds are each arranged separately.

As is clear from the above, in the injection mold according to the present invention, which is equipped with a large number of molds, the individual molds are thermally separated from each other, and at the same time, the individual molds can be easily centered in the axial direction. It has a structure.

Next, embodiments of the present invention will be described with reference to the drawings.

The illustrated injection mold includes a first mold half 4 that can be fixed to the injection molding machine via a fixing plate 2 and a second mold half 6 that can be moved relative to this mold half 4. It has The mold half 4 is a fixed plate 2
It holds two further plates 8, 10 located one after the other. Fixed position plate 1
0, a number of separate mold casings 12 are arranged. These mold casings 12 are, for example, 16 in total, in which case each of the 8 mold casings has 2 mold casings.
They may be arranged in rows or four rows of four mold casings each, or other purposeful arrangements are possible.

In the exemplary embodiment shown, the mold housings 12 have an outer housing 14 in which an inner housing 16 is arranged. There is a groove 1 on the outside of the inner casing 16.
8 are formed, these grooves 18 forming cooling passages in a known manner after insertion of the inner casing 12 into the outer casing 14. The cooling passage is provided with an inflow connection and an outflow connection for the cooling medium. The inner casing 16 serves as an outer contour mold forming the outer section of the parison, so that the circumferential surface of the hole provided in the inner casing 16 is
It serves as a mold surface 20 that forms the outer contour of the cavity 22 and thus defines the outer contour of the parison.

The mold member 2 is inserted into the hole 26 of the plate 10 whose position is fixed.
4 has been inserted. The mold member 24 has a hemispherical notch 28 on the outside.
forms the outer contour for the bottom of the cavity 22. The mold member 24 is further provided with a runner 30 which is connected to a runner distribution system 32 for hot water. The structure of the hot water runner distribution system is well known, so a detailed explanation thereof will be omitted. A recessed portion 34 is further provided on the outside of the mold member 24 and has a larger diameter than the hemispherical notch 28 and is coaxial with the hemispherical notch 28 . The recessed portion 34 includes a centering tube piece 36 formed on the end surface of the inner casing 16.
are engaged, and the end surface 38 of this centering tube piece 36
is in contact with the bottom of the recess 34 of the mold member 24.
Inner casing 16 to fixed position plate 10
The fastening takes place via the outer casing 14, ie by means of screws 40, as shown on the right in FIG.

As can be seen in the drawing, the separate mold casings 12, each with a mold surface 20, are fixed to the plate 10 in such a way that each mold casing 12 can follow the thermal expansion of the plate 10 independently of one another.

Mold half 6 movable relative to the injection molding machine
are plates 41 and 43 fixed in front and behind each other.
It has a base plate 42 configured as a double plate consisting of a double plate, and an intermediate plate 44 movable in the mold closing direction. intermediate plate 44
A neck mold, which will be described in more detail below, is arranged in the bottle and has an inner contour forming a bottle neck.

A leg section 46 of a mandrel-shaped core 48 forming the inner contour of the cavity 22 is held in the plate 43, which serves as a core holding plate. core 4
8 has an axial coolant guide channel 50 in the usual manner.
is provided. The connections of the coolant guide path 50 are constructed in a conventional manner and are therefore not shown.

A guide plate 5 is provided above the intermediate plate 44.
2 is fixed. Each guide plate 52 supports a two-part neck mold 54 so as to be able to slide laterally within the guide groove 53. Each neck mold half 56 is provided with an ejector pin 58 that extends through a through hole 60 provided in the guide plate 52, and the lower end of the ejector pin 58 is attached to the guide plate 52. It extends to the bottom. intermediate plate 4
4 are provided with undercut grooves 62 spaced apart from each other and extending perpendicularly to the sliding direction of the neck mold halves 56. In these grooves 62, an actuating rod 64 having a protrusion 61 on the side is inserted into the guide groove 5 of the guide plate 52.
3 so that it can slide at right angles to it. The pair of operating rods 64 are connected to each other via a yoke 65 at one end of the mold.
A cylinder of a drive device 67 in the form of a hydraulic piston-cylinder unit is fixed to the yoke 65, while a piston rod 69 of the drive device 67 is fixed to the yoke 65.
is rigidly connected to the intermediate plate 44. Grooves 66 are formed on the upper side of the actuating rod 64 and extend at an acute angle α with respect to the longitudinal axis of the actuating rod 64.
8 ends are engaged. The groove 66 is connected to both operating rods 64.
(see FIGS. 2 and 2a).

When the actuating rods 64 are slid longitudinally, the ejector pins 58 engaged in the grooves 66 are moved laterally by the grooves 66, thereby causing the neck mold halves 56 to move away from each other. It is made to move continuously in the direction.

The upper ends of both neck mold halves 56 have an inner contour 68 that corresponds to the desired contour of the bottle neck. The contour of the bottle neck may be, for example, a spiral profile if a screw cap is used as the closure, or a simple raised profile if a crown cork or similar closure is used. It's okay to be hot. In the case of a parison for producing bottles in a blow molding process, the inner contour 68 also forms the neck ring 63 necessary for holding the parison in a blow molding machine.

In order to position the neck mold 54 coaxially with respect to the inner casing 16, the neck mold 54 has a centering cone 70 on the outside that engages in a centering hole provided in the free end surface of the inner casing 16. There is. Further, a centering cone 72 may be provided that engages with a corresponding conical hole provided in the outer casing 14 starting from the end surface of the outer casing 14. With this configuration, the inner contour of the neck mold 54 is reliably and precisely centered with respect to the outer contour (mold surface 20) of the cavity 22.

The neck mold half 56 of each neck mold 54 further has a conical centering hole 74 extending from its bottom surface, and this centering hole 74 has a centering hole 74 formed at the lower end of the core 48. Works with Corn 76. This centering cone 76 and the centering hole 7 of the neck mold 54
4, the core 48 is centered within the mold surface 20.

In order to maintain the coaxial position of the core 48 with respect to the mold surface 20 even in the event of thermal expansion within the stationary plate 10, the leg section 46 of the core 48 is transversely mounted in the core holding plate 43, for example by means of a gap. It may also be held movable in a direction (not shown), so that the leg section 46 aligns with the centering hole 74 in the hole receiving the leg section 46 in the core holding plate 43 during mold closure. It can be moved in parallel to the axis via the cone 76 to a coaxial position with respect to the mold surface 20 . To enable this movement, the holes 81 provided in the intermediate plate 44 have a suitable diameter.

Another advantageous possibility of leg section adjustment for the core 48 is shown in FIG. In this embodiment, the leg section 46 of the core 48 is formed with a predetermined eccentricity relative to the axis of the core 48 itself and is held in a bushing 78. The outer circumferential surface of the bushing 78 is rotatable in a hole 80, which hole 80 is advantageously located coaxially with the mold surface 20 at room temperature, so that, relative to the outer circumferential surface of the bushing 78, the legs for the core 48 It has an eccentricity e2 equal to the eccentricity e1 of the section 46. It is configured like this. core 48
is steplessly movable parallel to the axis of a circular surface having a radius corresponding to the sum of eccentricities e1 and e2. As a result, the core 48 can be accurately centered on the mold surface 20 even if different thermal expansions occur between the base plate 42 and the stationary plate 10 during operation. A similar effect can be achieved, as shown in FIG. 1, by means of two bushings 78, in which the leg section 46 is located concentrically with respect to the core 48, one inserted into the other. This can also be achieved if the ring-shaped contact surfaces 82 of the two bushings 78 each have corresponding eccentricities e1 and e2. An externally operable rotary drive can also be provided for the bush 78.

Guide plate 5 for neck mold half 56
There is play within 2, and the mesh mold half 5
6 is advantageously adapted to follow the relative lateral movement between the mold casing 12 fixed on the stationary plate 10 and the intermediate plate 44 (due to the difference in thermal expansion between the two). be. The through hole provided in the guide plate 52 for the screw 55 may additionally or alternatively be provided with an interference margin. Coarse adjustment during assembly is performed as follows. That is, when the mold is closed, the guide plate 52 passes through the neck mold half 56.
Initially, screw 55 is lightly tightened so that it can be moved into its position at operating temperature. After the position is obtained, the guide plate 52 is fixed by further tightening the screws 55. Fluctuations in the operating temperature can be compensated for by corresponding tolerance-based play with positive interference. With this embodiment, the individual neck molds 54 can be adjusted independently of each other, which is a great advantage, for example, in injection molds for producing 16 or 32 parisons.

The axial translation of the core 48 in the cavity 22 causes the fixed position plate 1 to be heated by hot water.
0 and the base plate 42 due to the different thermal expansions. However, this axial translation can be completely or partially avoided or reduced by the measures described below. That is, the base plate 42 is provided with a heating device, and the heat supply of the heating device to the base plate 42 is adjusted in relation to the actual temperature detected at the representative temperature measuring point MP provided on the fixed plate 10. This is achieved by becoming more and more accommodating.

As can be seen from the foregoing, with the arrangement described above, all the members defining the mold can be adjusted coaxially with respect to a predetermined reference line on the fixed plate 10, so that the thermal expansion in the plate 10 is Whatever the size and direction, it does not affect the individual molds. This makes it possible, for example, to determine the individual mold casing in relation to the available cross section in an injection molding machine without taking thermal expansion into account. Furthermore, the division into individual mold casings offers the great advantage of being able to process a large number of similar workpieces of small size. This greatly simplifies production. Also, by dividing the neck mold into half neck molds for each mold, and by centering these neck molds as described above by the casing of each mold, the bottle The neck profile can be easily fabricated with virtually no flash formation or shifting.

A closing needle 84 is supported in the plates 8, 10 coaxially with respect to the axis of the cavity 22, the lower end 86 of which engages in the runner 30 in one end position and closes the runner. Close 30. Axially adjustable closure needle 8
4 is provided with a hydraulic drive device 88,
The drive 88 is driven via a piston 90 that can be loaded on both sides. A closing needle 84 with a thread 92 is screwed into the piston 90 . The adjustment position of the closing needle 84 is defined by a locking nut 94. It is advantageous if the drive 88 is controlled via a timing element. Drive 8 for closing needle 84
8 is thus controlled by a timing element, it is possible to precisely adjust the individual filling of the numerous cavities 22, thereby making it possible to extremely reduce the weight of the injected parison. It can be made uniform. By time-controlling the closing point of the closing needle 84, possibly in conjunction with the possibility of adjusting the inlet cross-section, the unavoidable Differences in the flow rate of the injected plastic and the resulting weight differences of the parisons can be adjusted.

Although the invention has been described above with respect to the manufacture of a parison with a bottle neck for making bottles by blow molding, the invention is however also applicable to other objects, particularly extending in the direction of movement of the mold. It can also be used for the production of objects whose length dimension is significantly larger than the width dimension perpendicular to the same direction of motion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the injection molding mold according to the present invention in a closed state, FIG. 2 is a plan view showing the closed position of the neck mold in the injection molding mold shown in FIG. 1, and FIG. The figure is a plan view showing the open position of the neck mold shown in figure 2, figure 3 is a sectional view taken along line - in figure 2, and figure 4 is a sectional view of the neck die shown in figure 2 for adjusting the leg section of the core. 2 is a diagram showing an embodiment and corresponding to a cross-sectional view taken along the line - in FIG. 1. FIG. 2... Fixed plate, 4, 6... Mold half, 8, 10
...Plate, 12...Type casing, 14...Outer casing, 16...Inner casing, 18...Groove, 2
0... Mold surface, 22... Cavity, 24... Mold member, 2
6... Hole, 28... Notch, 30... Runway, 32... Runner distribution system for high boiling water, 34... Recessed part, 36... Centering tube piece, 38... End face, 40... Screw, 41... Plate, 42... Base plate , 43... Core holding plate, 44... Intermediate plate, 46... Leg section,
48...Core, 50...Cooling medium guide path, 52...Guide plate, 53...Guide groove, 54...Neck mold,
55...screw, 56...neck mold half, 58...extrusion pin, 59...parison, 60...through hole, 61...
Projection, 62... Groove, 63... Neck ring, 64...
Operating rod, 65... Yoke, 66... Groove, 67... Drive device, 68... Inner contour, 69... Piston rod, 70,7
2...Centering cone, 74...Centering hole, 76...Centering cone, 78...Bush,
80, 81... Hole, 82... Contact surface, 84... Closing needle, 86... Lower end, 88... Drive device, 90... Piston, 92... Screw thread, 94... Locking nut, e
1, e2...Eccentricity, MP...Representative temperature measurement point, α
…acute angle.

Claims (1)

[Scope of Claims] 1. An injection molding mold equipped with a large number of molds for molding a parison with a bottle neck portion for manufacturing bottles by a blow molding method, which includes: (a) an injection molding machine; a fixed nozzle-side plate is provided, and an outer contour mold forming a generally cylindrical outer section of the parison is disposed on the fixed plate; Mold members are provided for forming the bottom contour, each of which is formed with a runner connected to a hot water runner distribution system provided on the fixed plate, and a drive a runner closing needle movable axially through the device and engaging the runner; (c) a core retaining plate movable relative to the injection molding machine; a leg section of the core that enters the outer contouring mold is fixed to the holding plate; (d) a neck mold is provided which is movable at right angles to the axis of the outer contouring mold; and the neck mold has an inner contour forming the outer shape of the bottle neck portion including a thread and a neck ring having a diameter larger than the thread, and is divided by a plane passing through the central axis of the bottle neck portion. and the same neck mold is disposed on an intermediate plate such that the intermediate plate is moved relative to the core holding plate in the direction of opening and closing of the injection mold when the core is withdrawn from the parison. (e) At least one hydraulic drive device is provided for the neck mold, and (f) the outer contour mold is connected to the inner casing 16.
The inner casing 16 is formed by a separate outer casing 14, and the peripheral surface of the hole provided in the inner casing forms a mold surface 20 defining the outer contour of the parison. The inner casing 16 is surrounded by an inner casing 16, and the outer casing is screwed on the end face side to the fixed plate 10.
(g) A separate neck mold 54 is assigned to each inner casing 16; (h) Each neck mold 54 is attached to the inner casing 16. a conical outer circumferential surface cooperating with the conical inner circumferential surface of the core 48 and coaxial with the bottle neck; and a conical inner circumferential surface cooperating with the conical outer circumferential surface of the core 48 and also coaxial with the bottle neck. (i) Each neck mold 54 is supported on an associated guide extending perpendicularly to the opening direction of the injection mold, and (v) located adjacent to each other. An injection molding mold having a large number of molds, characterized in that a common hydraulic drive device 67 for opening and closing the neck molds 54 is provided for each of the plurality of neck molds 54. 2. An injection mold according to claim 1, wherein the individual guides supporting the neck molds 54 are fixed to the intermediate plate 44 so as to be adjustable in the plane of the intermediate plate. 3. The core 48 is provided with a cylindrical leg section 46, the axis of which is located eccentrically with respect to the axis of the shaping section of the core 48, the leg section 46 being arranged on the core retaining plate. The injection mold according to claim 1, wherein the injection mold is rotatably supported in an eccentric hole of a bushing 78 which is rotatably supported in the bushing 43. 4. The core 48 is provided with a cylindrical leg section 46 concentric with the shaping section of the core, which leg section is connected to two relatively rotatable bushings, one located in the other. Core retaining plate 4 through
3. The injection mold according to claim 1, wherein the holes in both bushes are eccentrically arranged. 5. A pair of actuating rods 64 are supported on the intermediate plate 44 and are movable via a drive 67 at right angles to the direction of movement of the neck mold half 56;
The actuating rod is provided with a guide groove extending at an acute angle to the direction of movement of the actuating rod, into which an ejector pin 58 disposed in each neck mold half 56 engages. An injection mold according to claim 1.