JP4783092B2 - Pseudo core and injection mold using the same - Google Patents

Description

  The present invention relates to a pseudo core for supplying a label used for in-mold molding in which a label is integrally welded to the outer peripheral surface of a container product to be injection molded, and an injection mold using the same.

An in-mold label container that welds the label to the outer peripheral surface of the container to be injection-molded at the same time as the injection molding is provided in order to reduce the number of steps for attaching the label to the outer peripheral surface of the injection-molded container and to make the container excellent in appearance. Widely manufactured.
In order to obtain the in-mold label container by injection molding, the label is adsorbed on the outer peripheral surface of the pseudo core, and after inserting the label into the fixed cavity, the exhaust pressure is applied to the peripheral surface of the pseudo core, and the cavity side There has been proposed a method of supplying a label to an injection mold in which the label is received by a stationary mold side by an intake means (see, for example, Patent Document 1).
On the other hand, an in-mold temporary bonding method for in-mold labels has also been proposed in which an in-mold label having a surface specific resistance value equal to or greater than a predetermined value is temporarily bonded to a male or female cavity of an injection mold by static electricity. (For example, refer to Patent Document 2).

Japanese Patent No. 2797043 (pages 1-5, FIGS. 1-9) JP 2005-28838 A (pages 1 to 8, FIG. 1)

In the case of the label supply method of Patent Document 1, since the entire pseudo core is inserted into the fixed cavity, the label inserted in the narrow cavity for product molding is easily damaged by slight vibration of the pseudo core, Since the intake means is arranged in the fixed mold surrounding the cavity, there is a problem that the structure of the injection mold is complicated and expensive. In addition, in the case of injection molding without a label, there is also a problem that a mark of the air inlet opening opened on the inner peripheral surface of the fixed mold cavity appears on the outer peripheral surface of the molded container.
On the other hand, when the in-mold temporary bonding method of the in-mold label of Patent Document 2 is used, the special label is essential, and the material of the mold to which the label is temporarily bonded is also a material that is easily charged with static electricity. There was a problem of being restricted.

  The present invention solves each of the problems described in the background art, and can be securely inserted into a fixed mold cavity without using a special label and without damaging the label. It is an object of the present invention to provide a pseudo core and an injection mold using the same, which do not interfere with the injection molding.

Means for Solving the Problems and Effects of the Invention

As a result of research by the inventor of the present invention, the idea is that a pseudo core having a label adsorbed on the peripheral surface is inserted to the middle position of a fixed cavity, and the label is mechanically pushed into the back side of the cavity. It was made as a result.
That is, the pseudo core according to the present invention (Claim 1) has a tapered shape and an opening for suction, and is positioned on the outer periphery of the rear end of the peripheral wall and can advance and retreat along the axial direction of the peripheral wall. A label extruding means.

According to this, a label sucked in advance on the peripheral wall is inserted into a fixed cavity, which will be described later, and the suction is released, so that the label whose diameter is expanded by the elasticity of the label itself is applied to the inner peripheral surface of the cavity. At the same time, the rear end of the label is pushed into the back side of the cavity by a label pushing means such as a label pushing ring. For this reason, without using a special label as described above, and without damaging the label with the pseudo core, the label can be reliably inserted into a predetermined position in the cavity of the fixed mold and in-mold molding can be performed. In addition, since a special device such as a suction means is not required for the fixed mold, even a normal injection mold can be molded in-mold, and there is no problem in injection molding without a label. Accordingly, by properly using the pseudo core, both in-mold molding of a label and injection molding without a label can be performed.
The shape of the peripheral wall includes a generally conical shape, a substantially elliptical cone shape, a substantially quadrangular pyramid shape with rounded corners, a substantially hexagonal pyramid shape, and the like.
The label pushing means includes, for example, a label pushing ring having a through-hole that follows the cross-sectional shape of the peripheral wall, and a plurality of label pushing pins, which can be advanced and retracted by an air cylinder or the like. The
Further, the container obtained by in-molding the label may be a substantially conical shape having a bottom surface, a substantially elliptical cone shape, a substantially quadrangular pyramid shape with rounded corners, a substantially hexagonal pyramid shape, etc. Also included are cones, elliptical cones with a hemispherical convex tip, and quadrangular pyramids and hexagonal pyramids with rounded corners.

The present invention also includes an insertion / removal mechanism for inserting and removing the pseudo core including the peripheral wall and the pseudo core including the label pushing means between the opposed movable mold and the fixed mold, and the pseudo core. A pseudo core (Claim 2) is further included, which further includes an advancing / retracting mechanism that causes the peripheral wall to enter and exit the fixed cavity.
According to this, the in-mold of the label described above is inserted by inserting the pseudo core between the movable mold and the fixed mold facing each other, and allowing the peripheral wall of the pseudo core to enter and exit the fixed female cavity. Molding can be performed reliably. Moreover, by ejecting the pseudo core from between the movable mold and the fixed mold, injection molding without a label is possible.

For the insertion / removal mechanism and the advance / retreat mechanism, for example, a feed screw system such as a ball spline shaft and a fluid pressure cylinder such as an air cylinder or a hydraulic cylinder are individually used. Alternatively, the two mechanisms can be configured by a single articulated robot.
The peripheral wall of the pseudo core is substantially similar to the fixed cavity and has a shorter axial length than the cavity.
Furthermore, the pseudo core body includes a substantially conical shape having a substantially flat surface at the tip, a substantially elliptical cone shape, a substantially quadrangular pyramid shape with rounded corners, a substantially hexagonal pyramid shape, and the like.

  On the other hand, an injection mold according to the present invention (Claim 3) is an injection mold using the pseudo core, and has a male core and is a movable mold capable of approaching and separating from a fixed mold. And a fixed mold having a cavity for receiving the core, and a pseudo core body including the peripheral wall and the pseudo core including the label pushing means between the movable mold and the fixed mold facing each other. And a retracting mechanism for moving the pseudo core into and out of the fixed cavity.

According to this, the label sucked in advance on the peripheral wall of the pseudo core is inserted into the fixed cavity, and the suction is released, so that the label whose diameter is expanded due to the elasticity of the label itself is placed on the inner peripheral surface of the cavity. And the rear end of the label is pushed into the back side of the cavity by the label pushing means. In such a state, the pseudo core is allowed to escape from between both molds, and the movable core is entered into the cavity of the fixed mold, whereby the mold can be closed and in-mold (label) molding can be performed reliably. Then, after opening the mold for retracting the movable mold, taking out the product container attached to the movable core, and inserting a pseudo core with a new label sucked into the peripheral wall between both molds, in-mold Molding can be performed continuously and reliably.
Further, when the pseudo core is made to stand by at a position away from between both molds, injection molding without a label can be performed. For this reason, free injection molding is possible by an inexpensive modification by attaching a pseudo core having the above-described mechanisms to a normal injection mold.
In addition, the fixed cavity has a substantially conical shape having a bottom surface, a substantially elliptical cone shape, a substantially quadrangular pyramid shape with rounded corners, a substantially hexagonal pyramid shape, or a convex portion having a hemispherical tip. It has a shape such as a cone, an elliptical cone, a quadrangular pyramid with a rounded corner, and a hexagonal pyramid.

In other words, the present invention may include a pseudo core in which a product suction means extending toward the movable mold is disposed on the rear end side of the pseudo core main body.
In this case, after the in-mold label is formed, the product container attached to the movable core can be easily taken out by being sucked by the product sucking means, and the product sucking means and the pseudo core are supported in common. It can be attached to the means. For this reason, the product suction means and the pseudo core can be easily inserted and removed even in a narrow space between the fixed mold and the movable mold, and the intake path between the peripheral wall of the pseudo core and the product suction means should be shared. Can also be made more compact and easy to use.

In the following, the best mode for carrying out the present invention will be described.
FIG. 1 is a schematic view showing a pseudo core 1 of the present invention and an injection mold 30 of the present invention including the same.
As shown in FIG. 1, the pseudo core 1 includes a pseudo core body 3 that forms a substantially conical peripheral wall 2 having a tapered shape, and a substantially disk-like pseudo core that is fixed to a tip end of the pseudo core 1 via a bolt (not shown). An insert 4 and a label extrusion ring (label extrusion means) 8 located on the rear end side of the peripheral wall 2 are provided. The peripheral surface of the pseudo core insert 4 also forms a part of the peripheral wall 2.
A plurality of suction holes 6 are opened radially between the pseudo core body 3 and the pseudo core insert 4, and the suction holes 6 communicate with the intake passage 5 penetrating the pseudo core body 3. The suction hole 6 may have a slit shape along the circumferential direction of the peripheral wall 2.
The pseudo core body 3 is fixed to the distal end side of the long support member 9, and an intake passage 14 penetrating through the support member 9 communicates with the intake passage 5. The intake passage 14 is connected to a vacuum pump (not shown) on the base end side.

As shown in FIG. 1, a plurality of air cylinders 10 are fixed on the opposite side of the pseudo core body 3 in the support material 9, and a piston rod 13 connected to a piston 11 that slides in the cylinder chamber 12 is , Through the support material 9 and connected to the label extrusion ring 8. For this reason, by operating these air cylinders 10, the label push-out ring 8 can be advanced and retracted along the axial direction of the peripheral wall 2.
Product suction means 16 is attached near the center between the plurality of air cylinders 10 and on the rear end side of the pseudo core main body 3, and its hemispherical suction surface 17 is connected to the intake path 14 via the intake path 18. Communicate. The intake passage 18 may be communicated with a dedicated intake passage penetrating the support member 9 separately from the intake passage 14.

  As shown in FIG. 1, the support member 9 is fixed to the piston rods 25 and 26 of the air cylinders 23 and 24 on the base end side, and the air cylinders 23 and 24 are fixed to the moving body 20. A guide rod 22 and a ball spline shaft 21 pass through the moving body 20 and can move according to the rotation of the ball spline shaft 21 via a plurality of balls accommodated in an internal endless groove (not shown). Yes. That is, the spline shaft 21 and the moving body 20 are inserted between the fixed mold 31 and the movable mold 40 described below by moving the moving body 20 along the axial direction by the former rotation. Or the escape / insertion mechanism of the present invention is formed. Further, the air cylinders 23 and 24 and the piston rods 25 and 26 form an advance / retreat mechanism of the present invention that allows the pseudo core 1 to enter and leave the cavity 32 of the fixed mold 31 described below.

The fixed mold 31 and the movable mold 40 that constitute the injection mold 30 of the present invention together with the pseudo core 1 will be described below.
As shown in FIG. 1, the fixed mold 31 includes a female mold 35 having a female cavity 32 at the center and a cavity plate 36.
The cavity 32 includes a circular bottom surface 33 and a substantially conical inner peripheral surface 34 that gradually increases in diameter from the bottom surface 33 toward the opening, and the gate 39 that opens at the center of the bottom surface 33 includes a cavity. A sharp tip portion of the gate nozzle 38 that passes through the hollow portion (resin supply path) 37 of the plate 36 faces.
On the other hand, as shown in FIG. 1, the movable mold 40 includes a male plate 44 having a male core 42 projecting from the center, a stripper ring 45 disposed around the core 42, a stripper plate 46, and the above A core plate 48 adjacent to the rear end side of the male plate 44 is provided.

Next, the operation (action) of the aforementioned pseudo core 1 and the injection mold 30 including the same will be described.
In advance, the resin-made label L having elasticity is adsorbed to the peripheral wall 2 of the pseudo core 1 by a suction force through the suction passages 14, 5 and the suction hole 6 in advance at another standby place. After inserting the pseudo core 1 adsorbing the label L between the fixed mold 31 and the movable mold 40 by the insertion / removal mechanism (20, 21), the advance / retreat mechanism (23-26) allows the pseudo core 1 to be moved to FIG. As shown, the fixed mold 31 is advanced toward the cavity 32.
As shown in FIG. 2, the label L is longer in the axial direction than the peripheral wall 2 of the pseudo core 1 and has substantially the same length as the axial direction of the cavity 32, and is shown by a schematic sectional view in FIG. Thus, both end edges overlap with a constant width w in the radial direction. Note that the overlapping portion (w) is not necessarily formed.

Next, as shown in FIG. 3, the pseudo core 1 that has further adsorbed the label L is advanced toward the cavity 32 of the fixed mold 31, and the label L is brought closer to the inner peripheral surface 34 of the cavity 32. At this time, the peripheral wall 2 of the pseudo core 1 is slightly separated from the inner peripheral surface 34 of the cavity 32, and the plate 4 on the tip side of the pseudo core 1 is separated from the bottom surface 33 of the cavity 32. That is, the peripheral wall 2 is inserted to the middle position of the cavity 32 and stops.
In this state, the suction force via the intake passages 14 and 5 and the suction hole 6 is released. As a result, as indicated by an arrow in FIG. 4, the label L expands in the radial direction by its own elastic restoring force and comes into surface contact with the inner peripheral surface 34 of the cavity 32. At the same time, the rear end of the expanded label L comes into contact with the front end side surface of the label extrusion ring 8. At this time, as shown in the schematic cross-sectional view in FIG. 4, both ends of the expanded label L are slightly separated.

Next, as shown in FIG. 5, when the plurality of air cylinders 10 are driven and each piston rod 13 is extended, the label push-out ring 8 moves closer to the opening of the cavity 32 as indicated by the arrow in FIG. 5. Advance. The label L whose rear end is pushed by the label pushing ring 8 is pushed into the back side of the inner peripheral surface 34 of the cavity 32 while reducing the diameter in the radial direction, and stops at the bottom surface 33. At this time, as shown in the schematic cross-sectional view in FIG. 5, the diameter-reduced label L is in a state in which both end edges are in contact with each other and the entire inner peripheral surface 34 is in surface contact.
Here, the pseudo core 1 and the support material 9 are retreated from the fixed mold 31 side by the advance / retreat mechanism (23 to 26), and further, the fixed mold 31 and the movable mold 40 are disposed by the insertion / removal mechanism (20, 21). Escape to the outside waiting area.

Further, as indicated by the arrow in FIG. 6, the movable mold 40 is moved closer to the fixed mold 31 by an advance / retreat mechanism (not shown). Then, as indicated by an arrow in FIG. 7, the core 42 of the movable mold 40 is inserted into the cavity 32 of the fixed mold 31 and the mold is closed. At this time, the bottom surface 33 of the cavity 32 and the tip surface 43 of the core 42, and the inner peripheral surface 34 of the cavity 32 and the peripheral surface of the core 42 are parallel to each other with a certain gap therebetween, and are substantially conical closed products. The molding cavity c is formed, and the label L is laid along the inner peripheral surface 34 of the cavity 32.
In this state, as indicated by an arrow in FIG. 8, the molten resin material j that has passed through the hollow portion 37 of the fixed mold 31 is filled into the cavity c through the gate 39 and held for a predetermined time. At this time, the resin material j is integrated and solidified while being welded to the inner surface of the label L. As a result, a container (product) p having the label L integrally on the entire outer peripheral surface is formed.

Next, as shown by the arrows in FIG. 9, mold opening is performed to retract the movable mold 40 away from the fixed mold 31. At this time, the container p adheres to the core 42 of the movable mold 40 and moves together.
Furthermore, by the insertion / removal mechanism (20, 21), as shown by the arrow in FIG. 9, the pseudo core 1 and the support material 9 are inserted again between the fixed mold 31 and the movable mold 40, and the The pseudo core 1 is moved closer to the movable mold 40 by the advance / retreat mechanism (23 to 26). As a result, the product suction means 16 located on the opposite side of the support material 9 from the pseudo core 1 approaches the bottom surface of the container p. In this state, suction is performed through the intake passages 14 and 18, and the hemispherical suction surface 17 of the product suction means 16 is set to a negative pressure. At this time, the valve between the intake passage 14 and the intake passage 5 in the pseudo core 1 may be closed by operating a valve (not shown).

Then, an air cylinder (not shown) in the movable mold 40 is driven to advance the stripper plate 46 and the stripper ring 45 to the right as indicated by the solid line arrow on the left side in FIG. As a result, the stripper ring 45 comes into contact with the opening edge of the container p having the label L, and the container p is detached from the core 42 and moved to the right side. At substantially the same time, the bottom surface of the container p is adsorbed by the adsorbing portion 17 of the product adsorbing means 16 and supported in a cantilever state. Thereafter, the stripper ring 45 and the stripper plate 46 are moved backward as indicated by the dashed-dotted arrow on the left side in FIG.
The container p adsorbed and supported by the product adsorbing means 16 is moved from the movable mold 40 and the fixed mold 31 to an external standby place by the insertion / removal mechanism (20, 21) together with the pseudo core 1 and the support material 9. After being taken out, it is taken out by releasing the suction of the intake passages 14 and 18. As a result, a product container p having a beautiful appearance in which the label L is integrally welded to the outer peripheral surface can be obtained.

Further, a new label L is adsorbed on the peripheral wall 2 of the pseudo core 1 located at the standby place, and the newly-injected container p of the container p is subjected to the steps of FIGS. 2 to 8 described above. It is welded to the outer peripheral surface. By repeating the above operation, the container p in which the label L is in-molded can be continuously formed.
In the state shown in FIG. 9, when the pseudo core 1 is reinserted between the fixed mold 31 and the movable mold 40 together with the product suction means 16 and the support material 9, a new label L is applied to the peripheral wall 2. It may be adsorbed. In this case, as shown in FIGS. 2 to 5, the pseudo core 1 is advanced toward the stationary mold 31 by the advance / retreat mechanism (23 to 26) and the label push-out ring 8, and the label L adsorbed on the peripheral wall 2. 9 and 10, the previously formed container p is adsorbed and supported by the product adsorbing means 16 and taken out to an external standby place.

As described above, according to the pseudo core 1 and the injection mold 30 including the same, the label L sucked on the peripheral wall 2 of the pseudo core 1 is inserted into the cavity 2 of the fixed mold 31 and the suction is released. The diameter of the label L itself is increased by the elasticity of the label L itself and brought into contact with the inner peripheral surface 34 of the cavity 32. Further, the pseudo core 1 is allowed to escape from between the two molds 31 and 40, and the core 42 of the movable mold 40 is entered into the cavity 32 of the fixed mold 31 to close the mold, and in-mold molding using the label L can be performed reliably. Then, after opening the mold for retracting the movable mold 40 and taking out the container p adhering to the core 42 of the movable mold 40, the pseudo core 1 in which a new label L is sucked to the peripheral wall 2 is further attached to both molds 31, 40. By inserting in between, in-mold molding can be performed continuously and reliably.
Moreover, when the pseudo core 1 is made to stand by in a place away from between the fixed mold 31 and the movable mold 40, injection molding without a label can be performed. Therefore, for example, in-mold molding and non-label injection molding can be selectively performed by inexpensive modification by attaching the pseudo core 1 having the two mechanisms to a normal injection mold.

The present invention is not limited to the form described above.
For example, if the peripheral wall of the pseudo-core is substantially similar to the shape of the fixed cavity, the entire shape is substantially conical in addition to the above-mentioned form (2). It may be a substantially quadrangular pyramid, a hexagonal pyramid, or the like.
Moreover, the through-hole of the label extrusion ring which is a label extrusion means also becomes a thing according to the cross-sectional shape of the said surrounding wall. Alternatively, the label extruding means may be replaced with a plurality of label extruding pins so that the label is pushed into the inner side of the cavity.
Furthermore, the insertion / removal mechanism for inserting and removing the pseudo core between the fixed mold and the movable mold is not limited to the form using the ball spline shaft 21, but a fluid pressure cylinder such as an air cylinder or a hydraulic cylinder, or a multistage A telescopic boom or the like may be used.
In addition, the advance / retreat mechanism for moving the pseudo core closer to the fixed mold and retreating from this is not limited to the form using the air cylinders (23, 24), and may be a feed screw mechanism using the ball spline shaft 21 or the like, Alternatively, an articulated robot that also serves as an insertion / removal mechanism can be used.

Schematic which shows the pseudo core of this invention, and an injection mold using the same. Schematic which shows the effect | action of the said pseudo core. Schematic which shows the effect | action of the pseudo core following FIG. Schematic which shows the effect | action of the pseudo core following FIG. Schematic which shows the effect | action of the pseudo core following FIG. Schematic which shows the in-mold formation process following FIG. Schematic which shows the in-mold shaping | molding process following FIG. Schematic which shows the in-mold shaping | molding process following FIG. Schematic which shows the state which opened the mold after the said shaping | molding. Schematic which shows the state which takes out the molded product.

Explanation of symbols

1 ......... Pseudo core 2 ......... Peripheral wall 3 ......... Pseudo core body 6 ... ………… Suction hole 8 …………… Label extrusion ring (label extrusion means)
21 ………… Ball spline shaft (insertion / removal mechanism)
23, 24 ... Air cylinder (advance / retreat mechanism)
30 ………… Injection mold 31 ………… Fixed mold 32 ………… Cavity 40 ………… Movable L …………… Label

Claims (3)

A peripheral wall having a tapered shape and opening a suction hole;
Label pushing means located on the outer periphery of the rear end of the peripheral wall and capable of moving forward and backward along the axial direction of the peripheral wall,
A pseudo core characterized by that. An insertion / removal mechanism for inserting and withdrawing the pseudo core including the peripheral wall and the pseudo core including the label pushing means between the opposed movable mold and the fixed mold;
An advancing / retreating mechanism for allowing the peripheral wall of the pseudo core to enter and exit the fixed mold cavity,
The pseudo core according to claim 1 . An injection mold using the pseudo core according to claim 1 or 2,
A movable mold having a male core and capable of approaching and separating from the stationary mold;
A stationary mold having a cavity for receiving the core;
An insertion / removal mechanism for inserting and ejecting the pseudo core including the peripheral core and the label pushing means between the movable mold and the fixed mold facing each other;
An advancing / retreating mechanism for moving the pseudo core into and out of a fixed cavity,
An injection mold characterized by that.

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