JPH01199893A - Method and apparatus for covering container with plastic cap - Google Patents

Abstract

PURPOSE:To enable the number of forming and capping operations of plastic caps to be reduced, by heating to a softening point a thin plastic plate placed in close contact with the top opening edge of a container and deforming the same into a concave shape making use of the differences in pressure between the interior and exterior of the container. CONSTITUTION:A container 1 filled with a liquid content is positioned on a receiving stand 18 in a lower part of chamber 13 with an upper part thereof separated therefrom and a thin plastic plate 2a is fed therebetween. After the upper and lower parts 12 and 13 of a chamber are fixedly joined together, the inner pressure of the chamber 11 is decreased and a heater 26 is energized to heat the thin plastic plate 2a. A press plate 24 is thereafter moved downwardly and the thin plastic plate 2a is pressed against the top edge of the container 1 by an elastic portion 25 thereof, thereby forming an sealed space 8. After heating the thin plastic plate 2a to a softening point, the chamber 11 is communicated with the outside air to make the pressure of the space B lower than that of the exterior C, whereby the thin plastic plate 2a is deformed inwardly of the space B and into such concavely curved shape as 50 make close contact with the surface of the liquid content and finally shaped along the liquid surface and the inner peripheral surface of the container 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for attaching a concave cap formed from a thin plastic plate to an opening of a container filled with contents such as liquid, and this method. Relates to equipment used to carry out.

[Conventional technology]

FIG. 7 shows a container containing, for example, high viscosity ink.

In this type of container, contents are filled inside a metal can container 1, and a plastic cap 2 is attached to the opening of the container 1.
is installed. Furthermore, a metal or plastic M3 is fitted onto the opening of the container 1 from above the plastic cap 2. The plastic cap 2 is used as an inner lid, and this plastic cap 2
This prevents the contents from flowing out or scattering when the lid 3 is removed from the container 1.

Further, by using the plastic cap 2 as an inner lid, the contents of the container 1 are prevented from coming into contact with the outside air.

The conventional plastic cap 2 is manufactured by molding a thin plastic plate into a concave shape in advance, and after the contents are filled into the container 1, the plastic cap 2 is manually fitted into the opening of the container 1, and then the lid is closed. 3 is placed over container 1.

[Problem to be solved by the invention]

Conventionally, in addition to the molding process of molding the plastic cap 2, it is necessary to attach the plastic cap 2 to the container 1, which increases the number of man-hours required to complete the filling operation. Further, a large number of plastic caps 2 which have been previously formed into a concave shape are supplied to work in a stacked state, and an operator separates the plastic caps 2 one by one and manually attaches them to the container 1. However, since the plastic caps 2 are usually thin with a thickness of about 0.1 to 0.2 mm, it is extremely difficult and inefficient to separate the plastic caps 2 one by one from the stacked state. This is a typical work.

The present invention allows a plastic cap to be molded into a concave shape from a thin plastic plate and at the same time is attached to the opening of a container, thereby reducing the steps of forming and attaching the plastic cap and allowing efficient filling work. The purpose is to ensure that

[Means to solve the problem]

In order to achieve the above object, in the method of attaching a plastic cap to a container according to the present invention, a thin plastic plate is brought into close contact with the opening of a container filled with contents, and the pressure in the space inside the container is lower than the pressure outside the container. At the same time, the thin plastic plate that is in close contact with the opening of the container is heated and softened, and the thin plastic plate is deformed into a concave shape toward the inside of the container due to the difference in pressure between the space inside the container and the outside of the container.

Further, in the apparatus for attaching a plastic cap to a container according to the present invention, the following members are installed in a chamber communicating with an exhaust pump.

a) A receiving part for installing a container filled with contents b) A pressing member that presses the thin plastic plate in close contact with the opening of the container C) A heater (function) that heats the thin plastic plate that is in close contact with the opening of the container ] In the above method and apparatus, a thin plastic plate is brought into close contact with a container filled with contents, the pressure in the space inside the container is lowered than the pressure outside the container, and before and after this, the thin plastic plate is heated to soften it. By doing so, the thin plastic plate deforms into a concave shape in the direction of the space inside the container, forming a cap that fits tightly onto the surface of the contents.Furthermore, the plastic cap is attached to the opening of the container at the time it is molded. This eliminates the need to reattach a conventionally molded plastic cap to the container.Also, since the plastic cap tightly adheres to the contents, it prevents the contents from coming into contact with the air, and prevents the contents from coming into contact with air. The antioxidant effect is also increased.

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

First, an embodiment of an apparatus for attaching a plastic cap to a container according to the present invention will be described with reference to FIG. 1 (cross-sectional view).

In FIG. 1, reference numeral 11 indicates a chamber. This chamber 11 is composed of an upper chamber 12 and a lower chamber 13, and the upper and lower chambers 12 and 13 are
- It can be separated into upper and lower parts at the part indicated by line A. Separate means is provided for fixing the upper and lower chambers 12 and 13 to each other in a state where the upper chamber 12 and the lower chamber 13 are joined to each other as shown in FIG. This fixing means is constituted by, for example, a cylinder mechanism that presses the upper chamber 12 against the lower chamber 13, or a connector that connects and fixes the upper chamber 12 and the lower chamber 13 to each other.

A seal ring 14 is attached to the upper end surface of the lower chamber 13. When the upper chamber 12 and the lower chamber 13 are joined, the interior of the chamber 11 is sealed by the seal ring 14. An exhaust pipe 15 is attached to the upper chamber 12. This exhaust pipe 15 is the switching valve 1
It is connected to an exhaust pump 17 via 6. Switching valve 1
6 is a three-way valve, and this switching valve 16 controls the chamber 1.
1 to the exhaust pump 17, or the chamber 11
It can be switched so that the inside communicates with the outside air. By communicating the inside of the chamber 11 with the exhaust pump 17 through the switching valve 16 and driving the exhaust pump 17, the air inside the chamber 11 can be exhausted and the pressure inside the chamber 11 can be reduced to a vacuum or a state close to vacuum. There is.

A pedestal 18 is provided at the inner bottom of the lower chamber 13. The container 1 is positioned and installed on the upper surface of this pedestal 18. An elevating shaft 19 is connected to the lower surface of the pedestal 18. This elevating shaft 19 is inserted through the bottom plate 13a of the lower chamber 13 and extends outward from the bottom of the lower chamber 13. The elevating shaft 19 can slide against the bottom plate 13a of the lower chamber 13 via a seal ring 20. The elevating shaft 19 is driven in the vertical direction in the figure by a drive mechanism such as an air cylinder or a hydraulic cylinder.

This vertical movement of the lifting shaft 19 moves the pedestal 18 onto the bottom plate 13.
It can be lifted from a. With the pedestal 18 lifted away from the bottom plate 13a, the container 1
is installed on the pedestal 18 or the container 1 is taken out from the pedestal 18, thereby facilitating the work of carrying in and out the container 1.

A lifting shaft 21 is provided at the center of the upper plate 12a of the upper chamber 12.
is inserted. This lifting shaft 21 has a seal ring 27
It is designed to slide onto the upper plate 12a via the. Similar to the lifting shaft 19 provided on the bottom plate 13a side, the upper plate 1
The elevating shaft 21 on the side 2a is also driven in the vertical direction in the figure by a drive mechanism such as an air cylinder or a hydraulic cylinder provided outside the chamber. A support plate 22 is fixed to the lower end (inside the chamber) of the elevating shaft 21. A ring-shaped pressing plate 24 is fixed to the lower side of the support plate 22 by studs 23. Similarly, a ring-shaped elastic body 25 is adhered to the lower surface of the pressing plate 24. This elastic body 25 is made of hard rubber or resin. The diameters of the pressing plate 24 and the elastic body 25 are matched to the diameter of the opening of the container 1, and when the lifting shaft 21 is lowered, the elastic body 25 brings a thin plastic plate (described later) into close contact with the opening of the container 1. It is now possible to suppress the situation.

A heater 26 is provided inside the ring-shaped pressing plate 24 and the ring-shaped elastic body 25.

This heater 26 is constituted by, for example, a heating wire.

Reference numeral 31 is a cutter. This cutter 31 is ring-shaped and has a downward blade. The diameter of the cutter 31 is slightly larger than the outer diameter of the container 1, and when lowered, the cutter 31 surrounds the outer periphery of the container 1 with a gap in between. The cutter 31 is fixed to a support plate 32, and the support plate 32 is further connected to a lifting shaft 33. Three lifting shafts 33 are provided, each of which can slide with respect to the upper plate 12a via a seal ring 34. Although not shown, each lifting shaft 33
Their upper ends are connected to each other by a connecting member, and this connecting member is driven up and down by a drive mechanism such as an air cylinder or a hydraulic cylinder. By this operation, the respective lifting shafts 33 move up and down simultaneously, and the cutter 31 is driven up and down.

Next, a method of attaching a plastic cap to a container using the above-mentioned device will be explained.

The container 1 is, for example, a metal can, and an example of the contents is a liquid such as high viscosity ink. The thin plastic plate 2a that is the material of the plastic cap 2 has a thickness of 0.1
~0.2a+m, for example, polypropylene (p
p) and other thermoplastic resins.

FIG. 2 shows a state in which the upper chamber 12 and the lower chamber 13 are separated. The container 1 filled with contents is positioned and installed on the pedestal 18 in the lower chamber 13 with the chambers separated. At this time, the lifting shaft 19 inserted through the bottom plate 13a is raised, and the pedestal 18 is moved to the bottom plate 1.
If it is raised away from 3a, it becomes easier to position and install the container 1, making it suitable for assembly line work.

Further, when the upper and lower chambers 12 and 13 are separated as shown in FIG. 2, a thin plastic plate 2a is provided between the upper chamber 12 and the lower chamber 13.

Next, lower the upper chamber 12 and open the upper and lower chambers 12.
and 13 are joined. As shown in Figure 3, at this time,
The thin plastic plate 2a is sandwiched between the upper chamber 12 and the lower chamber 13. In the state shown in FIG. 3, the upper chamber 12 and lower chamber 13 are fixed so that they do not rub against each other. As a mechanism for this fixation, the upper chamber 12 may be pressed against the lower chamber 13 by cylinder pressure or the like, or the upper chamber 12 may be pressed against the lower chamber 13 by cylinder pressure or the like.
and the lower chamber 13 may be fixed to each other by means of a coupling device. As shown in FIG. 3, when the upper and lower chambers 12 and 13 are joined, a thin plastic plate 2a is installed at the opening of the container 1. Upper and lower chamber 12
and 13 are joined and fixed to each other, and the exhaust pump 1 is assembled.
7 is operated (at this time, the switching valve 16 is switched to communicate the inside of the chamber 11 with the exhaust pump 17), the air inside the chamber 11 is exhausted from the exhaust pipe 15, and the pressure inside the chamber 11 is reduced. Due to this evacuation operation, the container 1
Both the internal space B (the space above the contents) and the external space C of the drawer 1 are reduced in pressure and become vacuum or near-vacuum pressure. Also, before and after the exhaust operation, the heater 26 is energized and the heater 26 starts heating the plastic thin plate 2a.

Next, the lifting shaft 21 is lowered, the pressing plate 24 provided at the lower part is lowered, and the thin plastic plate 2a is pressed against the edge of the opening of the container 1 by the elastic body 25 provided on the lower surface of the pressing plate 24. . The pressure of the cylinder driving the lifting shaft 21 is applied to the thin plastic plate 2 through the elastic body 25.
Press a and attach the thin plastic plate 2 to the green opening of the container 1.
a are brought into close contact with each other, and the space B inside the container 1 is sealed.

After the thin plastic plate 2a is heated to a temperature sufficient to soften it by the heater 26, the exhaust pump 17 is stopped and the switching valve 16 is switched to open the chamber 11.
The interior is communicated with the atmosphere. At this time, the outer part C of the container 1 in the chamber 11 returns to atmospheric pressure, but since the space B inside the container 1 is sealed with the thin plastic plate 2a, this space B remains under reduced pressure. Therefore, the pressure in the space B inside the container 1 becomes lower than the pressure outside the container 1.

Due to this pressure difference, the heated and softened plastic thin plate 2a is deformed into a concave shape into the space B of the container 1, as shown in FIG. Due to this deformation, the thin plastic plate 2a comes into close contact with the liquid surface of the contents, and is formed into a shape that follows the liquid surface and the inner peripheral surface of the container 1. Thereafter, the elevating shaft 33 is lowered, and the ring-shaped cutter 31 trims the portion of the thin plastic plate 2a that protrudes from the outer periphery of the container 1. The state after trimming is shown in FIG. The thin plastic plate 2a is in close contact with the inner circumferential surface of the opening of the container 1 and has a concave shape that is in close contact with the liquid surface of the contents, and the outer circumferential portion 2b of the thin plastic plate 2a protrudes to the outside of the container 1. The product completed in the state shown in FIG. 5 is taken out from the chamber 11. This removal operation separates the upper chamber 12 from the lower chamber 13 and raises the pedestal 18 by the lifting shaft 19 to a position away from the bottom plate 13a. Then, the container 1 is carried out from the elevated pedestal 18.

Thereafter, a metal or plastic lid 3 is fitted into the opening of the container 1. At this time, the portion 2b of the thin plastic plate protruding from the container 1 is bent along the outer surface of the container 1 by fitting the M3, and as shown in FIGS. 6 and 7, it is almost the same as the conventional one. The molding and mounting of the plastic cap 2 having the same shape is completed.

In addition, in the above-described apparatus and method, the timing at which the thin plastic plate 2a is heated by the heater 26 is as follows.
It may be done either before or after the pressure inside the chamber is reduced, and in some cases, after the pressure inside the -H chamber is reduced, heating of the thin plastic plate 2a may be started at the same time as the switching valve 16 starts introducing outside air into the chamber 11. .

In addition, in the device shown in the figure, the cutter 31 is installed in the chamber 11, but the cutter 31 is not installed in the chamber 11, and the container 1 is moved into the chamber after the plastic thin plate 2a is deformed as shown in FIG. The thin plastic plate 2a may be removed from the inside of the plastic plate 11 and then trimmed by another device.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

According to the method of the present invention, the thin plastic plate is deformed into a cap shape and attached to the container at the same time, which is compared to the conventional process of molding a plastic cap and fitting the molded product into the container. The number of beetles can be significantly reduced.

Moreover, the plastic cap is molded into a shape that tightly fits the contents of the container by reducing the pressure in the interior space of the container. Therefore, no air remains between the plastic cap and the contents, and even after the carb molding is completed,
Outside air no longer touches the contents. Therefore, compared to the conventional method of attaching a plastic cap by hand, it is possible to enhance the antioxidant effect of the contents.

According to the apparatus of the present invention, it is possible to simultaneously form a plastic cap and attach it to a container within the chamber.

Furthermore, by providing a cutter in the chamber,
It is now possible to complete the molding of the plastic cap within the chamber, and the container taken out from the chamber is fitted with an almost completed plastic cap.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of an apparatus for attaching a plastic cap to a container according to the present invention, and FIGS. 5 is a sectional view showing the container taken out from the chamber; FIG. 6 is a sectional view of the container after the molding of the plastic cap is completed; FIG. 7 is a sectional view showing the container and It is a perspective view showing a lid. 1... Container, 2... Plastic cap, 2a.
...Plastic thin plate, 11...Chamber, 12...
- Upper chamber, 13...Lower chamber, 16...
Switching valve, 17...exhaust pump, 18...cradle, 24
...Press plate, 25...Elastic body, 26...Heater, 31-...Cutter. Agent Patent Attorney Teruo Nozakij −i ′ Figure 5 Figure 6

Claims (1)

[Claims] 1. A thin plastic plate is brought into close contact with the opening of a container filled with contents to lower the pressure in the space inside the container than the pressure outside the container, and is brought into close contact with the opening of the container. Method 2 of attaching a plastic cap to a container by heating and softening a thin plastic plate, and deforming the thin plastic plate into a concave shape toward the inside of the container due to the difference in pressure between the space inside the container and the outside of the container. The pressure in the space inside the container and the outside of the container is lowered below atmospheric pressure, and after a thin plastic plate is brought into close contact with the opening of the container, the outside of the container is returned to atmospheric pressure, so that the pressure in the space inside the container is lower than the pressure outside the container. 3. A method for attaching a plastic cap to a container according to claim 1, wherein the thin plastic plate is deformed into a concave shape toward the inside of the container, and then the thin plastic plate is trimmed to be slightly larger than the outer diameter of the container. Method 4 for attaching a cap to a container: Apparatus for attaching a plastic cap to a container, which is equipped with the following members in a chamber communicating with an exhaust pump: a) A receiving part for installing a container filled with contents; b) Plastic. c) A pressing member that presses the thin plate in close contact with the opening of the container; c) A heater 5 that heats the thin plastic plate that is in close contact with the opening of the container; 5. The apparatus for attaching a plastic cap to a container according to claim 4, further comprising a cutter that operates in a direction to cut the plastic cap.