JPH0366133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of forming a tube container for storing pasty contents such as toothpaste, mustard, wasabi, etc.

(Background Art) FIG. 4 shows a sectional view of a tube container 10 to be obtained.

The tube 11 is a laminated tube made of laminated metal foil and synthetic resin sheet, and has a container opening 1 at one end.
2 are molded and fixed together. In the next step, this tube container is used by injecting and filling the contents from the opening at the other end of the tube, and sealing the opening by heat welding.

By the way, this tube container 10 is a tube 1.
In order to increase the bonding strength between the tube 1 and the container mouth 12, the tip of the tube at the bonding portion is bent slightly inward to increase the bonding area.

The inventor has developed a molding method for integrally molding the container opening 12 of such a tube container 10 onto one end of the tube 11 by injection extrusion, and has already filed a patent application (Japanese Patent Application No. 81581/1983).
issue).

FIG. 5 shows a molding die used in the above molding method.

This mold is a 3-plate type,
A fixed mold 13, an intermediate mold 14, and a movable mold 15 are provided.

The intermediate die 14 is supported on a rotary plate 16 by a lift spring (not shown) or the like. Further, the intermediate mold 14 includes an intermediate mold main body 18 having a tube insertion hole 17, a split mold 19 forming a cavity surface (hereinafter referred to as "cavity surface") that regulates the outer shape of the container opening, and a tip end in the tube insertion hole 17 of the intermediate mold main body 18. A tube presser 20 provided so as to be freely protrusive and retractable is provided.

The movable mold 15 is fixed to a movable platen 21 that can move up and down. Then, the movable mold 15 enters the tube insertion hole 17 of the intermediate mold 14 in the downward movement position, and the core member 23 defines a cavity 22 for molding the container opening with its tip surface and the cavity surface of the split mold 19.
and an upright wall 24 that receives mold clamping force when the mold is closed. A pressing member 25 made of a spring piece is provided on the outer circumferential surface of the base of the core member 23, and as described later, presses the tube 26 to bend its tip slightly inward along the cavity surface and the tapered surface. 27 is a tube holding cylinder and the tube presser 20 mentioned above.
The tube 26 is pressed and held by the tube presser 20 and the core member 23.

In order to mold a tube container configured as described above, the tube 26 is first inserted into the tube insertion hole 17 of the intermediate mold 14. At this stage, the lower end of the tube 26 has not yet been bent.
Next, the movable mold 15 descends together with the movable platen 21, and its core member 23 enters the tube 26. When the pressing member 25 made of a spring piece comes into contact with the end surface of the tube 26, the end surface of the tube 26 is pressed and the tube 26 is pressed.
6 moves downward, and as a result, the tip of the tube 26 is slightly bent inward along the tapered wall of the cavity surface.

After that, when the movable mold 15 further descends, the tube 2
6 becomes difficult to descend any further, so the pressing member 2
5 loses its elastic force, the pressing member 25 rides on the tube and descends while sliding on the outer peripheral surface of the tube. When the lower surface of the upright wall 24 of the movable mold 15 comes into contact with the upper surface of the intermediate mold 14, the movable mold 15 and the intermediate mold 1
4 also descends and closes against the fixed mold 13. After the mold is closed, the tube presser cylinder 27 is driven to press the tube presser 20, and the tube presser 20 presses and holds the tube 26 between it and the core member 23.

Next, molten resin is injected into the cavity 22 from the hot runner portion of the fixed mold 13, and is cooled and solidified to obtain a desired tube container.

The tube holder 20 described above is for holding the tube 26 so that the tube 26 does not slip out of the cavity 22 due to injection pressure.

Note that the intermediate mold 14 is connected to the rotary plate 1 as shown in FIG.
There are 3 units placed at regular intervals on top of 6.
The tube is inserted at the X position, injection molding is performed at the Y position located between the movable mold 15 and the fixed mold 13, and the molded product is taken out at the Z position, making continuous molding possible. There is.

(Problems to be Solved by the Invention) However, it has been found that even this conventional molding method has the following problems.

That is, since the bent portion at the tip of the tube 26 is formed by the elastic force of the pressing member 25, the bending length of the bent portion can only be adjusted by adjusting the elastic force of the pressing member 25. However, delicate adjustment of this elastic force has been extremely difficult.

More specifically, in the case of multi-cavity molding, or in the case where continuous molding is performed by sequentially rotating a plurality of intermediate molds 14 to the position of the movable mold 15 and fixed mold 13 as described above, each intermediate mold Since the shape of the cavity surface of each cavity of the mold 14 is slightly different, and the contact friction of the tip of the tube with the tapered wall of the cavity surface is slightly different, it is necessary to set a common elastic force of the pressing member 25 suitable for each intermediate mold. becomes extremely difficult. In addition, the tube itself has variations in wall thickness and bending resistance, so even if there is a single cavity, there will be differences in the bending length, which increases the reject rate and also increases the number of tube containers with different lengths. There were various problems such as not being able to mold it with a mold.

Therefore, the present invention was made to solve the above problems, and its characteristics are that the bending length of the tip of the tube is uniform, high quality products can be obtained at a high yield, and the bending length can be adjusted. Another object of the present invention is to provide a method for molding a tube container that can be easily performed.

(Means for Solving the Problems) In order to solve the above problems, the present invention has the following configuration.

That is, the tip of a pre-formed tube is inserted into a fixed mold cavity, the mold is then closed, a core member erected in a movable mold is fitted into the tube, and then fixed to the tip of the core member of the movable mold. In a method for molding a tube container, in which the cavity formed by the cavity surface of the mold and the tube end interposed therebetween is filled with resin, and the container opening is integrally molded and fixed to one end of the tube, the core is removed from the side of the core member. A holding means for pressing and holding the tube on the member is provided in the movable mold, and when the movable mold reaches a predetermined position before the completion of mold closing, the holding means is activated to hold the tube on the core member, and then It is characterized by completely closing the mold and bending it inward along the tube tip and cavity surface.

(Function) The tube inserted into the fixed cavity is
When the movable mold reaches a predetermined position before closing the mold, the holding means presses and holds the movable mold against the core member of the movable mold,
Moves down with the movable mold.

Therefore, the tip of the tube is inserted along the tapered wall of the cavity surface and bent slightly inward.

The holding position of the tube by the holding means is constant,
Since the tube always moves down a certain distance along with the movable mold, the bending length is always constant regardless of the shape of the cavity surface and other conditions, and a tube container of uniform quality can be obtained.

Furthermore, by changing the actuation timing of the holding means (by adjusting the gap s shown in FIG. 2), the amount of bending of the tip of the tube can be changed arbitrarily.

Furthermore, if the holding position of the tube by the holding means is set close to the fixed mold, tubes with the same diameter but different capacities (lengths) can be molded using the same mold.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

First, an example of a molding die used in the method of the present invention will be explained with reference to FIG.

Reference numeral 30 denotes a movable mold, which is attached to a movable platen of a mold opening/closing device (not shown) and moves toward and away from the fixed mold 31 . The movable mold 30 includes a mounting plate part 32 for attaching to the movable platen, standing walls 33a and 33b extending integrally from the mounting plate part 32 in the direction of the fixed mold 31, and the standing walls 3.
3a and 33b, and is fixed to the mounting board part 32 at its upper end, and the tip part is connected to the upright wall 33.
A core member 34 is provided that protrudes downward from the lower surface.
Although not shown, a cooling water circuit is formed within the core member 34 .

Further, the core member 34 is formed into a cylindrical shape, and the outer shape of the distal end portion is formed to match the inner surface shape of the mouth of the tube container to be obtained.

The fixed mold 31 is attached to a fixed platen of a mold opening/closing device (not shown). Fixed mold 31 has tube insertion hole 3
5 is formed. The lower part of the tube insertion hole 35 is constricted into a substantially funnel shape to form a cavity surface 36 that regulates the outer shape of the container mouth. When the mold is closed, the tip of the core member 34 of the movable mold 30 enters the tube insertion hole 35 with the tube 37 interposed, and the tip surface of the core member and the cavity surface 36 define a cavity 38 for molding the container mouth. do.

39 is a hot runner for injecting and filling the cavity 38 with molten resin.

40a is a clamp cylinder, and the movable type 30
The rod 41a is fixedly provided at the lower part of the upright wall 33a, and the rod 41a moves forward and backward into a through hole 42a provided in the upright wall 33a toward the core member 34. At the tip of this rod is tube 37.
A holding member 43a is fixed to hold the core member 34 with clamping pressure between the core member 34 and the outer periphery of the core member 34. The distal end surface of the holding member 43a is formed into a substantially 1/2 arcuate surface that follows the arcuate surface of the outer diameter of the tube 37.

Further, a similar cylinder device including a clamp cylinder 40b and a holding member 43b fixed to its rod 41b is provided at an opposing position on the other upright wall 33b side.

Both cylinder devices constitute tube holding means.

Therefore, the tube 37 is held between the core member 34 and the core member 34 by the holding members 43a and 43b over substantially the entire circumference thereof.

In addition to the normal mold opening/closing control position detector, the mold opening/closing device is installed at a predetermined distance S from the mold closing completion position (Figure 2).
A position detector P (not shown) for detecting the position of the movable mold 30 at the front position is provided with a detection position S that can be freely adjusted. A detection signal from the position detector is input to a drive device (not shown) for the clamp cylinders 40a, 40b, and the clamp cylinders 40a, 4
0b is driven and moves a predetermined distance S from the mold closing completion position.
At the front position, as described above, both holding members 43
a, 43b are controlled so as to hold the tube 37 under pressure between it and the core member 34. Further, the driving device for the clamp cylinders 40a, 40b is activated by the injection process completion signal.
is controlled to restore it.

It goes without saying that the mold opening/closing device described above can be controlled by an appropriate sequence including the mold opening/closing control position detector, the position detector P at the S position, and the like.

Next, the molding operation procedure will be explained together with the method of the present invention.

First, in the mold open state, the tube 37 is inserted into the tube insertion hole 36 of the fixed mold 31. At this time, the lower end of the tube 37 has not yet been bent (FIG. 1). Next, start mold closing. As a result, the movable mold 30 descends toward the fixed mold 31, and the core member 34 enters the tube 37. When the movable mold 30 reaches a position a distance S in front of the fixed mold 31, a signal is emitted from the position detector P, and this signal causes the clamp cylinders 40a, 4
The drive device 0b operates and the clamp cylinder 40
Pressure oil is supplied to the rear chambers a and 40b, and the rod 41
a, 41b and the holding member 43 fixed thereto
a and 43b move forward in the direction of the core member 34, and both holding members 43a and 43b hold the tube 37 with pressure between them and the core member 34 (FIG. 2).

Therefore, when the movable mold 30 further descends, the tube 37 also descends with the movable mold 30, and the tip of the tube is pushed along the tapered wall of the cavity surface 36, so that it is slightly bent inward.

When the mold closure is completed, molten resin is injected and filled into the cavity 38 via a hot runner 39 from an injection device (not shown) (FIG. 3).

The tube holding means simultaneously prevents the tube 37 from coming out of the tube insertion hole 35 due to injection pressure.

After the injection process is completed, clamp cylinder 40
a and 40b in the opposite manner to the above to open tube 3.
7 is released, and after cooling and solidifying, the mold is opened to obtain a tube container in which the container opening is integrally molded and fixed.

In addition, since the tube holding means is provided at the lower part of the upright wall 33 of the movable mold 30, that is, close to the fixed mold 31, even if the tubes have different lengths, the tube 37 can be held by the tube holding means. It is possible to push the tube in and bend the tip of the tube by a predetermined amount, and tube containers with the same diameter but different capacities (lengths) can be molded using the same mold.

The amount of bending of the tip of the tube can be easily adjusted by changing the detection position of the movable mold 30 by the position detector P.

Although the position detector P was provided in the mold opening/closing device in the above embodiment, it may also be provided in the mold, and the driving of the holding means is not dependent on the position of the movable mold, but is based on the elapsed time from the start of mold clamping. It may also be controlled by timing. Further, the holding means may not be based on a cylinder but may be based on mechanical means such as a cam device or a link device.

Furthermore, although the above embodiments have been explained using a two-plate mold as an example, it goes without saying that the method of the present invention can be similarly applied to a three-plate mold as shown in FIG. .

(Effects of the Invention) As described above, according to the method of the present invention, since the tube is reliably held by the tube holding means and pushed in a certain amount, even if there are variations in the wall thickness, length, etc. of the tube, Furthermore, even if there are variations in shape on the mold cavity surface, etc., the tip of the tube can always be bent uniformly by a certain amount, so tube containers of uniform quality can be molded with a high yield.

Furthermore, the amount of bending of the tip of the tube can be easily adjusted by simply changing the timing at which the tube is held.

Moreover, no special adjustment is required even in the case of a multi-cavity mold or a mold using a plurality of fixed molds (intermediate molds).

Furthermore, by holding the tube close to the fixed mold, various advantages can be achieved, such as tubes with the same diameter but different capacities (lengths) can be molded using the same mold.

[Brief explanation of drawings]

The drawings show an example of a molding die suitable for carrying out the present invention; FIG. 1 is a sectional view before the mold is closed, FIG. 2 is a sectional view of the tube held by the tube holding means, and FIG. A cross-sectional view during injection is shown. Figure 4 is a sectional view showing an example of the tube container to be obtained;
The figure is a sectional view of a conventional molding die, and FIG. 6 is a plan view of the entire conventional molding apparatus. 10...Tube container, 11...Tube, 1
2... Container opening, 13... Fixed type, 14... Intermediate type, 15... Movable type, 16... Rotating plate, 17...
Insertion hole, 18...Intermediate mold body, 19...Split mold, 2
0...Tube presser, 21...Movable plate, 22...
Cavity, 23... Core member, 24... Standing wall, 25... Pressing member, 26... Tube, 27
...Tube holding cylinder, 30...Movable type, 3
1...Fixed type, 32...Mounting board part, 33a, 33
b... Standing wall, 34... Core member, 35... Tube insertion hole, 36... Cavity surface, 37... Tube, 38... Cavity, 40a, 40b... Clamp cylinder, 41a, 41b... Rod, 4
2a...through hole, 43a, 43b...holding member.

Claims (1)

[Claims] 1. The tip of a pre-formed tube is inserted into a fixed mold cavity, the mold is then closed, a core member erected in a movable mold is fitted into the tube, and then a core member of a movable mold is inserted into the movable mold cavity. In a method for forming a tube container, the cavity is formed by a tip end surface of a member and a fixed cavity surface, and a resin is filled into the cavity with the end of the tube interposed therebetween, and a container opening is integrally molded and fixed to one end of the tube. The movable mold is provided with a holding means that presses and holds the tube against the core member from the side of the member, and when the movable mold reaches a predetermined position just before the completion of mold closing, the holding means is actuated to hold the tube against the core member. A method for molding a tube container, which comprises holding the tube in place, then completely closing the mold, and bending the tip of the tube inward along the cavity surface.