JP4225628B2 - Heating device for thermoforming sheet and film materials - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a heating apparatus for a thermoforming sheet / film material, and more particularly to a heating apparatus for a thermoforming sheet / film material in which a release sheet is provided for releasing a heated object on a rectangular contact panel heater.
[0002]
[Prior art]
Conventionally, as a heating device that heats a sheet or film material for thermoforming, for example, a nonwoven fabric substrate containing thermoplastic resin fibers, to a molding temperature, a contact heating device that heats a rectangular contact panel heater in contact with the sheet or film material The type of heating device is well known.
As shown in FIG. 5, the contact heating type heating device is used to smoothly disengage the thermoforming sheet / film material as the object to be heated 4 from the rectangular contact panel heaters (hereinafter referred to as heaters) 1 and 2. Usually, the surfaces of the heaters 1 and 2 are covered with release sheets 5 and 6 made of a mesh film made of Teflon.
[0003]
Conventionally, the release sheets 5 and 6 have been formed in a rectangular shape corresponding to the heaters 1 and 2, and two opposite sides or four sides are fixed to the heaters 1 and 2, etc. When the heating of the object 4 is completed and transported to the forming stage, the heaters 1 and 2 are vertically separated from each other with the object to be heated 4 interposed therebetween. A large negative pressure is generated between 1 and 2 and the object to be heated 4, and the release sheets 5 and 6 are brought into close contact with the object to be heated 4 as shown in FIG. It becomes a state. In this state, the object to be heated 4 is conveyed to the forming stage. However, since the release sheets 5 and 6 are restrained by the heaters 1 and 2 with respect to the conveyance movement of the object to be heated 4, 4 is caught by the release sheets 5 and 6, and damage such as wrinkles is generated on the article to be heated 4 as shown in FIG.
Therefore, conventionally, in order to solve this problem, the start of conveyance is delayed until the object to be heated and the release sheet are completely separated from each other, but the temperature of the object to be heated is lowered, which causes molding defects. ing.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems of the prior art, and the target treatment is to damage the object to be heated after the applied pressure during heating by the heater to the object to be heated is removed. An object of the present invention is to provide a heating device that can immediately convey an object to be heated and to improve molding defects due to insufficient molding temperature of the object to be heated.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a sheet / film material heating apparatus according to the present invention is provided with a release sheet for releasing a heated object on a rectangular contact panel heater as described in claim 1. In the heating device for thermoforming sheets and film materials, at least the release sheet to be installed on the lower rectangular contact panel heater is fixed to the heater end on the front side of the heated object in the conveying direction. In addition, the other three sides are set in a free state, and tension applying means for applying tension to the sheet by pulling the sheet rearward with respect to the conveyance direction of the heated object is provided on the side opposite to the fixed side. .
The tension applying means can be a weight or a spring.
[0006]
[Operation and effect of the invention]
In the heating apparatus for a thermoforming sheet / film material of the present invention configured as described above, when the heating of the object to be heated is completed and transported to the forming stage, the heater is moved up and down across the object to be heated. Even when separated vertically, the lower release sheet is pulled by the tension applying means and is always held in a tensioned state. Therefore, even if a large negative pressure is generated between the heater and the object to be heated, at least the lower release sheet does not come into close contact with the object to be heated and is not lifted from the heater surface. As a result, the molds are released in a linear fashion from the front end side in the transport direction.
Also, even if the lower release sheet is pulled due to the transport movement of the heated object, the lower release sheet is movable, so it can move with the heated object, and the heated object can be transported. Does not hinder movement. Therefore, there is no risk of damage such as wrinkles on the object to be heated.
As a result, the object to be heated can be transported to the molding stage immediately after the completion of heating, and molding defects due to insufficient molding temperature are improved.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 includes a pair of rectangular contact panel heaters (hereinafter abbreviated as heaters) 1 and 2 arranged opposite to each other, and at least the upper heater 1 is a piston-type cylinder device. It is comprised so that it can raise / lower vertically by the drive device 3 which consists of these.
[0008]
This heating device A is a contact heating type heating device, and is a thermoforming sheet made of an article to be heated 4 between the upper and lower heaters 1 and 2, for example, a nonwoven fabric base material containing thermoplastic resin fibers. A film material is introduced, and at least the upper heater 1 is driven by the driving device 3 to move vertically downward, and the object to be heated 4 is sandwiched between the upper and lower heaters 1 and 2 to be heated on both upper and lower surfaces of the object to be heated 4. The object to be heated 4 is heated in a state where the pressures 1 and 2 are brought into contact and a necessary pressure is applied.
[0009]
The sheet / film material for thermoforming, which is the object to be heated 4, is held by a clamp (not shown) and is conveyed from the heating stage to the molding stage. In the figure, it is conveyed in the direction of arrow a. Is done.
[0010]
The upper and lower heaters 1 and 2 of the heating apparatus A are respectively covered with release sheets 5 and 6 on the heater surface, that is, the contact surface with the object to be heated 4.
The release sheets 5 and 6 are made of a Teflon film formed in a mesh shape, and are attached to the upper heater 1 with two or four opposite sides fixed to the side surface of the heater 1 or the like. Only one side is fixed to the heater 1 at 2.
[0011]
A release sheet 6 (hereinafter referred to as a lower release sheet) that is attached to the lower heater 2 and covers the heater surface of the heater 2 has one side in the conveying direction of the thermoforming sheet / film material of the heater. On the other hand, only one side is fixed to the side end portion which is the front side (hereinafter referred to as the front end portion for convenience of explanation), and the other three sides are in a free state where they are not fixed anywhere.
[0012]
The lower release sheet 6 is provided so as to extend from the front end portion of the heater 2 on the heater surface toward the rear side with respect to the conveying direction of the heated material 4, and the rear portion is the heater end portion in the direction ( In the following description, for the sake of explanation, it will be referred to as a rear end part). Further, the roller surface is suspended downward via a tension roller 7 provided so that the roller surface is substantially flush with the heater surface. The weight 8 is attached.
[0013]
Accordingly, the lower release sheet 6 is always pulled to the rear side with respect to the conveyance direction of the article to be heated 4 so that tension is applied, while the gravity of the weight is directed toward the front side in the conveyance direction of the article to be heated 4. If the above force is applied, it will be movable in that direction.
The weight is configured by stacking a plurality of weight plates 8a, and the tension force can be adjusted by increasing or decreasing the number of weight plates 8a or exchanging the weight plates 8a.
[0014]
In the heating apparatus A of the present embodiment configured as described above, the heating of the article to be heated 4 is completed, and the heaters 1 and 2 are vertically separated while sandwiching the article to be heated 4 when transported to the forming stage. The lower release sheet 6 is always held in a tensioned state by being pulled by the weight 8, and even if a negative pressure is generated between the heaters 1, 2 and the article to be heated 4, the release sheet 6 is not heated. In close contact with 4, the center part does not rise from the heater surface. Therefore, the article to be heated 4 is released in a linear manner sequentially from the front end side in the carrying direction with the carrying movement.
In addition, even if the release sheet 6 is pulled by the transport movement of the article to be heated 4, the release sheet 6 is movable, so that the transport movement of the article to be heated 4 is hindered and the article to be heated is wrinkled. There is no risk of damage.
Therefore, it becomes possible to convey to the molding stage immediately after the completion of heating, and molding defects due to insufficient molding temperature of the article 4 to be heated are improved. In addition, the molding cycle can be shortened.
[0015]
Next, FIG. 2 shows a second embodiment. In the above-described embodiment (referred to as the first embodiment), the lower release sheet 6 is tensioned by pulling the lower release sheet 6 with a weight. In contrast, the lower release sheet 6 is tensioned by pulling the rear end of the lower release sheet 6 with respect to the heated object transfer direction with a spring 9. is there. The remaining structure of this embodiment is not substantially different from that of the first embodiment.
[0016]
Similar to the lower release sheet 6 of the first embodiment described above, the spring 9 only fixes one side to the front end of the lower heater 2 and frees the other three sides, starting from the front end of the heater 2. The heater surface is extended toward the rear side with respect to the conveying direction, and is attached to the lower end side of the lower release sheet 6 suspended via the tension roller 7 on the rear side of the heater. It is elastically stretched over the apparatus A installation floor.
This embodiment also has the same operations and effects as those of the first embodiment, but the first embodiment has an advantage that tension can be easily adjusted.
[0017]
Next, FIG. 3 shows a third embodiment, and FIG. 4 shows a fourth embodiment. The third embodiment is a modification of the first embodiment, and includes not only the lower release sheet 6 but also the third embodiment. The upper release sheet 5 also has only one side fixed to the front end portion of the upper heater 1 on the front side with respect to the heated object transport direction, and the side opposite to this side is placed on the rear portion of the heater 1 via the tension roller 7 ′. It is made to hang down and is pulled by a weight 8 ′ so as to apply tension to the upper release sheet 5.
[0018]
Further, the fourth embodiment is a modification of the second embodiment, and not only the lower release sheet 6 but also the upper release sheet 5 is fixed to the front end portion of the heater 1 only on one side. The opposite sides are hung downward at the rear part of the heater 1 via a tension roller 7 ′, pulled by a spring 9 ′, and tension is also applied to the upper release sheet 5.
The third embodiment and the fourth embodiment also have the same operations and effects as the first and second embodiments described above.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a thermoforming sheet / film material heating apparatus according to a first embodiment of the present invention, in which FIG. Each of the states when the object to be heated is conveyed to the forming stage after completion is shown.
FIGS. 2A and 2B are cross-sectional views showing a second embodiment of the present invention, in which FIG. 2A shows a state where an object to be heated is heated, and FIG. 2B shows a state where heating is completed and the object to be heated is conveyed to a molding stage. Each state is shown.
3A and 3B are cross-sectional views showing a third embodiment of the present invention, in which FIG. 3A shows a state in which an object to be heated is introduced between upper and lower heaters, and FIG. 3B shows a state in which the object to be heated is heated. (C) shows the state when heating is completed and the object to be heated is conveyed to the forming stage.
4A and 4B are cross-sectional views showing a fourth embodiment of the present invention, where FIG. 4A shows a state in which an object to be heated is introduced between upper and lower heaters, and FIG. 4B shows a state in which the object to be heated is heated. (C) shows the state when heating is completed and the object to be heated is conveyed to the forming stage.
FIGS. 5A and 5B are cross-sectional views showing a conventional heating device for thermoforming sheet / film material, where FIG. 5A shows a state in which an object to be heated is introduced between upper and lower heaters, and FIG. 5B shows a state in which the object to be heated is heated. (C) shows the state when heating is completed and the object to be heated is transported to the molding stage.
[Explanation of symbols]
A: Heating device 1: Upper heater 2: Lower heater 4: Heated object 5: Upper release sheet 6: Lower release sheet 8: Weight (tension applying means)
8 ': Weight (tensioning means)
9: Spring (tensioning means)
9 ': Spring (tensioning means)

Claims (3)

In a heating device for a thermoforming sheet / film material in which a release sheet is provided for releasing a heated object on a rectangular contact panel heater, a release sheet provided on at least the lower rectangular contact panel heater Fix only one side to the heater end on the front side with respect to the conveyance direction of the object to be heated, make the other three sides free, and convey the sheet to the side opposite to the fixed side A heating apparatus for a thermoforming sheet / film material, characterized by comprising tension applying means for applying tension to the sheet by pulling rearward with respect to the direction. The heating device for thermoforming sheet / film material according to claim 1, wherein the tension applying means is a weight. 2. A heating apparatus for a thermoforming sheet / film material according to claim 1, wherein the tension applying means is a spring.

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