JPH0627388Y2 - Heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a heating device, and more particularly to a heating device for heating and softening a sheet when vacuum forming a food container or the like from a plastic sheet.

[Conventional technology]

For example, an egg pack or a container for jelly or ice cream is generally made of polypropylene, polyethylene, etc. between the heaters (2) (2) ... A thermoplastic plastic sheet (3) (hereinafter referred to as a sheet) is passed through to soften by heating, and then the softened sheet (3) is pressed by an upper die and a lower die of a molding apparatus (not shown), and Air is drawn from the air holes punched in the mold to bring the sheet into close contact with the mold, and when the sheet is cured, compressed air is ejected from the air holes to remove the molded sheet from the mold, and finally a punching device (not shown). The individual containers are punched out and molded.

As the heating means of the sheet (3) in the heating device (1), rod-shaped sheathed heaters (2) (2) ... As shown in FIG. 7, and above the sheet (3), the sheet (3) A large number are arranged so as to be orthogonal to the feeding direction, and are arranged parallel to the feeding direction of the sheet (3) on the lower side, or are arranged so as to be orthogonal to the feeding direction of the sheet (3) in the same manner as the upper side to perform heating. In some cases, a plurality of infra heaters (5) in which a heating source (not shown) is embedded in substantially rectangular ceramics (4) (4) shown in FIG. is there.

[Problems to be solved by the device]

The sheathed heater shown in FIG. 7 has the advantages of being inexpensive, easy to handle, and quick to rise to a predetermined temperature, but it is difficult to heat the surface of the sheet evenly, and uneven firing occurs. It has the drawback of being easy. If firing unevenness occurs, when pressing with a later molding device,
The adhesion between the sheet and the mold becomes poor, and it becomes difficult to mold the container uniformly and accurately. For this reason, generally, the infra heater shown in FIG. 5, which is capable of uniformly heating the sheet surface by arranging the heating source in a plane, is widely used. Is expensive, and since it holds a large number of heating sources, its wiring and installation are complicated, and its heavy weight makes it inoperable and slows the rise to a predetermined temperature. There is a drawback in that the heating must be continued even when the operation is stopped such as during lunch breaks, resulting in a large energy loss.

In view of the above-mentioned problems, the present invention is a heating device which is inexpensive, easy to handle, quick to rise to a predetermined temperature, and capable of uniformly heating each part of a sheet to reduce uneven burning. The purpose is to provide.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a heating device for heating the plastic sheet by a plurality of sheath heaters arranged in parallel above and below a plastic sheet that intermittently moves in a certain direction. The sheath heater arranged on the upper side is arranged in a direction orthogonal to the moving direction of the plastic sheet, and the sheath heater is reciprocally rocked in a direction parallel to the feeding direction of the plastic sheet by using a rocking mechanism. It is what

[Action]

According to the above configuration, the heating device according to the present invention is inexpensive and easy to handle, and the sheathed heater that quickly rises to a predetermined temperature is reciprocally rocked in parallel with the sheet feeding direction. The surface can be heated on average.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

(11) is a sheet and is fed by a feed roller provided outside the heating device (10) or a sprocket wheel for feeding (neither is shown) in the direction of the arrow in FIG. According to the width of the die (not shown) when pressing, it moves by a constant pitch.

(12) (12) ... are upper heaters for heating the sheet (11) at about 900 ° C., and the upper heaters (12) (12)
A sheathed heater in which a U-shaped heating source is integrally covered with quartz is used as. Above Upper Heater (12) (12)
Are arranged above the seat (11) and orthogonal to the feeding direction of the seat (11), and the side walls (14) of the two terminal boxes (13) (13) facing each other face each other. ) (1
Insert it into 4) with both ends protruding slightly, and at this time, the upper heaters (12) (12) of the side walls (14) (14) ...
The insertion holes (15) (15) of the are made oblong, and the upper heaters (12) (12)
The structure that does not hinder the swinging motion of the seat (11) in the moving direction. Inside the terminal box (13) (13), the wiring (42) for the upper heaters (12) (12) ..., the control device (not shown), etc. are housed, and the side surface of the heating device (10) is further accommodated. Oscillating plates (16) (16), which are slightly shorter than the length of, are arranged so as to face each other. Upper heaters (12) (12) in terminal box (13) (13)…
Both ends of the are inserted into the rocking plate (16) and fixed to the rocking plate (16) by appropriate means. Outside the side walls (14) (14),
The L-shaped locking body (18) (18) is fixed, and the L-shaped locking body (18) (18) is fixed.
Between them, an upper box (21) having a heat insulating material (20) attached thereto is arranged and fixed inside the bottom wall (19). With the above-mentioned configuration, the upper heaters (12) (12) ... are provided on the side walls (14) (14) of the terminal boxes (13) (13) and the bottom wall (19) of the upper box (21).
As a result, the upper heater (12) (1
2) The heat generated in… is concentrated and applied to the sheet (11),
Combined with the action of the heat insulating material (20) attached to the bottom wall (19) of the upper box (21), it becomes possible to improve the thermal efficiency of the upper heaters (12) (12).

The structure of the support mechanism (C) for the oscillating plate (16) is shown in FIG.
This will be described below with reference to FIG. 3 showing a cross section taken along the line A and a partially cutaway perspective view of FIG.

(22) (22) is a roller support member fixed by screws or the like near both ends in the longitudinal direction of the swing plates (16) and (16),
Upper guide rollers (23) (23) having a vertical rotation axis are provided at the upper ends of the roller supports (22) (22), and in the lower end in a direction parallel to the upper heaters (12) (12). Lower guide rollers (24), (24) having a rotating shaft are rotatably attached by pins or the like. The upper guide rollers (23) (23) are concave grooves of the upper guide pieces (25) (25) fixed inside the terminal boxes (13) (13) and on the side walls (14) (14). (26) (26) is slidably fitted, and the lower guide rollers (24) (24) are also inside the terminal boxes (13) (13) and the bottom wall (43) (43). ) The concave groove of the lower guide piece (27) (27) fixed on the top
(28) Fits in (28) slidably. With the above configuration, the rocking plate (16) can freely rock in parallel with the feeding direction of the sheet (11).

In FIGS. 1 and 2, (29), (29), ... Are sheets (1
Below the 1), and a plurality of lower heaters arranged in parallel to the feed direction of the seat (11), (30), when the sheet (11) hangs due to thermal expansion, the lower heater (29) ( 29) ... Wire mesh for preventing contact with the sheet (11).

4 and 5 show a specific example of the mechanism for performing the reciprocal swing motion of the swing plate (16).

Reference numeral (31) is a crankshaft attached to the output shaft (33) of the speed reducer (32), and the rotation of the motor (34) connected to the speed reducer (32) is clamped by a crank pin (35). It is converted into the reciprocating motion of the arm (36). (37) is a crank arm connecting plate having one end pivotally attached to the crank arm (36) and the other end fixed to the rotating shaft (38), and (39) is the crank arm connecting plate (37). One end is fixed to the rotary shaft (38) while keeping a substantially right angle, and the other end is pivotally attached to one end of the slider (40) to form a slider connecting plate.

The other end of the slider (40) is pivotally attached to the swing plate (16). Further, the rotating shaft (38) is extended to the vicinity of the oscillating plate (16) which faces the rotating shaft via the bracket (44) fixed to the outer wall of the heating device (10), and the slider connecting plate is the same as described above. It is connected to the oscillating plate (16) via the (39) and the slider (40).

With the above configuration, the crank arm (36) performs a vertical reciprocating motion by the rotational motion of the motor (34), and the rotary shaft (38) performs a rotary motion by the vertical reciprocating motion of the crank arm (36). As a result, the reciprocating oscillating motion of the oscillating plate (16) is achieved. As shown in FIG. 6, if the swing pitch (P) at this time is set to about half of the arrangement pitch (P ') of the upper heaters (12), (12), the average pitch of the seat (11) is increased. Heating is possible.

The crank arm (36) may be provided with a length adjusting mechanism such as a turnbuckle, and the positions of the motor (34) and the speed reducer (32) are not limited to the original position. Further, the crank arm connecting plate (37) and the slider connecting plate (39) may be eliminated and the crank arm (36) may be directly connected to the slider (40), and further, another swing mechanism, for example, a cam mechanism. A servo mechanism or the like can also be used.

[Effect of device]

As described above, according to the present invention, it is possible to reliably eliminate the uneven burning of the sheet, and as a result, when pressing in the molding process, the adhesion between the sheet and the mold is improved and the uniformity of the container is improved. Accurate formation is possible, and thus improvement in product precision can be achieved. Also, as a heater, a sheath heater that is cheap and easy to handle and that quickly rises to a predetermined temperature is used, so productivity is improved and heating can be performed only when necessary, which is a great energy saving effect. Is obtained.

[Brief description of drawings]

1 is a partial front sectional view of a heating device according to the present invention, FIG.
1 is a sectional view taken along the line BB in FIG. 1, FIG. 3 is an enlarged sectional view taken along the line AA in FIG. 2, and FIG. 4 shows the structure of the crank mechanism and the support mechanism of the rocking plate. The partially broken perspective view of the heating device shown,
FIG. 5 is an enlarged view showing the connecting structure of the crank arm and the oscillating plate, and FIG. 6 is an operation explanatory view showing the relationship between the pitch (P ') of the oscillating motion and the arrangement pitch (P) of the upper heater. FIG. 7 is a side sectional view of a conventional heating device, and FIG. 8 is a perspective view showing an example of a conventional heater. (10) …… Heating device, (11) …… Plastic sheet, (12) …… Upper heater, (29) …… Lower heater.

Claims (1)

[Scope of utility model registration request] 1. A heating device for heating the plastic sheet by a plurality of sheath heaters arranged in parallel above and below a plastic sheet which intermittently moves in a fixed direction, wherein a sheath heater disposed at least above the sheath heater is provided. A heating device which is arranged in a direction orthogonal to the moving direction of the plastic sheet, and which causes the sheathed heater to reciprocally swing in a direction parallel to the feeding direction of the plastic sheet by using a swinging mechanism.