JP4122955B2 - Vacuum plug for plastic bubble sheet manufacturing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vacuum plug for a plastic bubble sheet manufacturing apparatus. This plug is convenient for maintenance of the apparatus because it can be removed by breaking it by hitting it from the surface in a state of being fitted to the vacuum suction cavity of the manufacturing apparatus.
[0002]
[Prior art]
A plastic bubble sheet (hereinafter referred to as “bubble sheet”), which is made of a plastic film vacuum-molded with many caps and a flat plastic back film bonded to the bottom, is used for cushioning packaging and other materials. Used in a wide range of fields. A typical method for producing this type of bubble sheet is to prepare a vacuum forming roll in which a metal cylinder having a large number of vacuum suction cavities on its surface is supported rotatably about an axis. -It consists of the process of putting the film of the molten plastic extruded from the die | dye, shape | molding said cap film by vacuum forming, and fuse | melting the molten plastic extruded from another T-die as a back film.
[0003]
As shown in FIG. 1A (cross-sectional view) and FIG. 1B (plan view), the structure near the vacuum suction cavity in the vacuum forming roll is formed by machining a metal cylinder (1) to obtain a vacuum suction cavity (2 ) Are formed, a vacuum plug (5) made of a metal plate is fitted to the bottom, and a vacuum passage (4) is provided from the back to an internal vacuum suction passage (not shown). It is a thing. A number of notches serving as air flow paths are provided around the vacuum plug, and the air in the cavity (2) is sucked in vacuum to form an air flow path (between the vacuum plug and the cavity ( 3) through the vacuum passage (4) to the vacuum suction path.
[0004]
The vacuum plug (5) is prepared separately from the vacuum forming roll and disposed by fitting, of course, because it is convenient for maintenance. In the operation of this apparatus, the air flow path (3) and the portion behind the air flow path (3) are often clogged with molten resin or foreign matter, and thus are restored by exchanging and cleaning the vacuum plug. Therefore, the vacuum plug is required to be hard to cause clogging and to be easily replaceable when clogging occurs.
[0005]
The air flow path (3) formed between the vacuum plug and the vacuum forming cavity has a shape that satisfies the requirements of the vacuum plug described above, and has a substantial influence on the shape of the bubbles to be formed. Must not give. The applicant has devised a vacuum plug of the “cross slit” type having a flat shape as shown in FIG. This vacuum plug exhibits excellent performance as far as the above requirements are concerned, and when being replaced, it is divided into two or four by hitting the vicinity of the center while being fitted to the vacuum suction cavity. It was convenient in that it could be removed. However, the production requires two steps of punching a circular plate and forming slits, and the slitting step is particularly troublesome, and there is a problem that the cost of producing the vacuum plug increases accordingly.
[0006]
It is desired that a recent bubble sheet is manufactured in a wide width for convenience of use and for a request for improvement in productivity at the time of manufacture. As a result, the vacuum forming roll is also widened, and it is desirable to increase the roll diameter in order to increase the line speed, and accordingly, the number of vacuum suction cavities, that is, the number of vacuum plugs becomes enormous. It is obvious that the great effort required to manufacture the vacuum plug not only calls for the high cost of the bubble sheet manufacturing apparatus, but also brings a significant disadvantage to maintenance.
[0007]
Therefore, the inventors intend to manufacture a vacuum plug by punching a plate by a press, that is, in one step, and a planar vacuum plug shown in FIG. 3, that is, a circular vacuum corresponding to a vacuum suction hole having a circular cross section. A shape having four notches forming an air flow path provided at equal intervals on the circumference as a semicircular receding portion was manufactured and tested. This vacuum plug was superior in terms of performance in that vacuum suction could be suitably performed without substantially affecting the shape of the cap to be molded, but the vacuum plug as a countermeasure against clogging Upon replacement, it was experienced that it was difficult to break and remove like the above-described cross slit type vacuum plug.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a vacuum plug that is compatible with a vacuum plug used in an air bubble sheet manufacturing apparatus, which is easy in manufacturing process at the time of manufacture and easy to remove by cracking during maintenance. .
[0009]
[Means for Solving the Problems]
The vacuum plug of the plastic bubble sheet manufacturing apparatus of the present invention that achieves the above object is to manufacture a plastic bubble sheet in which a large number of caps are formed by vacuum forming of a plastic film, and a flat plastic film is bonded to the bottom surface thereof. In the apparatus, a plug to be fitted to the bottom of a number of vacuum suction cavities provided around a metal hollow roll to be vacuum formed, and for a metal plate having a shape suitable for the shape of the vacuum suction cavity, Recessed parts are provided at a plurality of surrounding locations so that an air flow path can be formed between the vacuum suction cavity, and a V-shaped groove is provided on the back surface so as to cross the cross , and a blow is applied from the front surface. It is easy to take out by splitting .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A specific example of this vacuum plug is a flat shape as shown in FIG. 3, that is, a circular shape corresponding to the cross-sectional shape of the vacuum suction cavity being a normal circular shape, and a receding part ( 6) is semi-circular and is provided at four equal intervals on the circumference, which is the same as the prototype described above. The feature is that a groove (7) having a V-shaped cross section on the back surface is provided, and in the vacuum plug having the planar shape of FIG. 3, this groove is formed in the opposite half as shown in FIGS. It is appropriate to connect the circular centers. As can be easily understood from this shape, this vacuum plug can be divided into two or four parts by hitting the vicinity of the center of the surface through a chisel or the like while being fitted in the vacuum suction cavity. Easy to remove.
[0011]
As the material for the vacuum plug, select a material that is easy to process and that is easy to break when hit. Phosphor bronze and duralumin are preferred. In particular, duralumin has a high thermal conductivity and is suitable as a material for vacuum forming roll parts of a bubble sheet manufacturing apparatus. In short, the V-shaped groove is combined with an appropriate selection of width and depth so that there is virtually no risk of breaking when fitted and placed, while it is easy to break when hit and cracked. Produced is a cross-sectionally V-shaped groove with the above-mentioned width and depth appropriately selected on one side of the material plate, crossing vertically and horizontally at a pitch according to the size of the plug. In addition, it can be efficiently carried out by punching the plate with a press at a pitch synchronized with the groove.
[0012]
【Example】
6000 vacuum plugs arranged at the bottom of a vacuum suction cavity having the following dimensions and having the shape shown in FIGS. 3 to 5 were manufactured using a duralumin plate as a material.
Vacuum suction cavity diameter: 10.0mm Depth: 4.0mm
Plug diameter: 8.0mm Thickness: 2.0mm
Groove width: 0.8mm Depth: 0.5mm
[0013]
This vacuum plug was placed in a vacuum suction cavity of a vacuum forming roll having an outer diameter of 300 mm (periphery 942 mm) and a width of 600 mm. The fitting was made easy by pushing in using a special jig and driving lightly. The clogged material used for producing the bubble sheet was able to be removed by hitting the chisel with a sharp tip at the center of the vacuum plug and hitting it lightly with a hammer.
[0014]
【The invention's effect】
The vacuum plug of the present invention can be manufactured significantly easier than a cross slit type vacuum plug. The cross slit type vacuum plug is a combination of two steps of punching and slitting, and slitting requires a lot of labor. In some cases, it will be easily understood in view of the fact that machining is an easy task of forming grooves on the plate.
[0015]
In this way, the vacuum plug of the present invention in which the production cost is significantly reduced is cracked if it is hit near the center if it is removed from the vacuum forming roll for maintenance when clogging occurs. It has the benefit of a cross slit type vacuum plug that can be easily removed.
[Brief description of the drawings]
FIG. 1 is a view showing a structure near a vacuum suction hole in a vacuum forming roll of a plastic bubble sheet manufacturing apparatus, wherein A is a cross-sectional view and B is a plan view.
FIG. 2 is a plan view showing a cross slit type vacuum plug.
FIG. 3 is a plan view from the surface showing an example of the vacuum plug of the present invention.
4 is a plan view of the vacuum plug of FIG. 3 viewed from the back side.
5 is a cross-sectional view taken along the line II of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal cylinder 2 Cavity 3 Air flow path 4 Vacuum passage 5 Vacuum plug 6 Retreat part 7 Groove of V-shaped cross section

Claims (3)

In a device for producing a plastic bubble sheet in which a cap film having a large number of caps is formed by vacuum forming of a plastic film and a flat plastic back film is bonded to the bottom surface of the metal hollow roll for vacuum forming. A vacuum plug that fits to the bottom of a number of vacuum suction cavities provided around the vacuum suction cavity by providing retraction parts at multiple locations around the metal plate having a shape that matches the shape of the vacuum suction cavity. A plastic characterized in that an air flow path can be formed between them, and a groove having a V-shaped cross section is provided on the back surface so as to cross the cross, and it is easy to take out by hitting and cracking from the front surface. Vacuum plug for bubble sheet manufacturing equipment. The shape of the vacuum suction hole is circular, and the approximate shape of the vacuum plug is circular, the retracted part is semicircular and is provided at four equal intervals on the circumference, and the cross section of the back surface is V-shaped. The vacuum plug according to claim 1, wherein the groove is provided so as to connect the centers of the semicircular surfaces facing each other. The vacuum plug according to claim 1 or 2, which is manufactured using phosphor bronze or duralumin as a material.

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