JPH0611165Y2 - Inner frame of clamp for sandwiching sheet material for thermoforming - Google Patents

Description

[Detailed Description of the Invention] Industrial field of application The present invention is a thermoforming device that is sandwiched between sheet-like materials to be formed in thermoforming such as vacuum forming, pressure forming, and press forming, is separated from a forming die, and is located outside thereof. Regarding the clamp inner frame of the machine.

Prior Art As shown in FIG. 1, a pair of upper and lower clamp inner frames 6 and 7 for sandwiching a sheet-shaped material 1 formed by a conventional thermoforming machine.
Is formed into a rectangular frame consisting of four sides,
Separate from the molding die 2 and assemble it by welding a square steel bar or angle steel so that it has an outer dimension, that is, an inner dimension that is expanded by a proper die gap a from the dimension of the die base, or cut out an iron plate,
Each of them is bridged to a clamp outer frame 4, 5 which is connected to a moving device (not shown). Further, as shown in FIG. 2, when the sheet-shaped material 1 is press-molded between a pair of male and female molding dies 2a and 2b, the sheet-shaped material 1 has a peripheral edge formed in a pair of clamps formed in a rectangular frame shape. It is sandwiched by the frames 6 and 7.

During such thermoforming, the sheet-shaped material 1 to be formed is subjected to a stress that is drawn inward in the inner frame of the clamp. For this reason, when an angle steel is welded and assembled like a conventional clamp inner frame, or when an iron plate is cut out, the clamping pressure is concentrated at the four corners of the clamp inner frame when the sheet-shaped material is clamped. There was a defect that the sheet-shaped material was likely to come off in the middle of the side of the inner frame.

Therefore, as shown in FIG. 3, a rubber cushion material 21 is attached to the surface of the upper and lower clamp inner frames that sandwich the sheet-shaped material 1 of the angle steels 11 and 12, or as shown in FIG. When the material 17 is a laminated sheet of the thermoplastic base sheet 16 and the fibrous material 15 having poor moldability, the fibrous material 15
Screw 18 that is screwed into the angle steel 13 on the side, is fixed with a lock nut 19, and has its tip protruding to the sandwiching surface of the angle steel 13.
This prevents the sheet-shaped materials 1 and 17 from coming off the inner frame of the clamp.

Problems to be Solved by the Invention However, in the case where the cushioning material is adhered to the clamping surface of the clamp inner frame of the conventional example, clamping pressure may be insufficient at the time of molding and durability is insufficient, and the clamping When the tip of the screw is projected on the surface, the sheet-shaped material is pinched only at the location of the screw, so the sheet-shaped material corrugates inside the clamp inner frame, especially in the case of vacuum forming, the sheet is not It is difficult to make a so-called airtight state in which the outer edge is continuously contacted.

Further, when the sheet-shaped material is a laminated sheet of a thermoplastic base sheet and a fiber material with little elongation, and when expanded at a high ratio during thermoforming, the fiber material cannot withstand expansion and is fixed with screws on the sandwiching surface. It could be torn from the part that was cut.

Means for Solving the Problems In the clamp inner frame of the present invention, which is separated from the molding die and is located on the outer side of the mold and which clamps the sheet material for thermoforming, the clamp inner surfaces of the pair of upper and lower clamp inner frames are provided. Since the heights of the inner frames of the clamps change inward and outward and the terraces meshing with each other are provided, the conventional problems can be solved.

Action As illustrated in FIG. 5, when the sheet-shaped material 1 is sandwiched by the upper and lower clamp inner frames 23 and 24 and is formed by, for example, the vacuum forming mold 2, the sheet-shaped material 1 is clamped by the clamp inner frame 2
3, 24 is pulled inward. At this time, when a plurality of terraces 22 are provided on the holding surfaces 21 of the clamp inner frames 23 and 24 as shown in FIGS.
When 3 and 24 approach and pinch the sheet-shaped material 1, first, the sheet-shaped material 1 is brought into contact with each ridge line 34 of the terrace 22, and then the sheet-shaped material 1 is pinched by being firmly meshed. Therefore, even if a large force for expanding the sheet-shaped material 1 is applied during thermoforming, the sheet-shaped material 1 does not come off from the clamp inner frames 23, 24.

This means that the sheet material 1 is a fibrous material 1 having poor molding elongation.
A laminate of 5 and the thermoplastic base sheet 16 is particularly advantageous because it does not come off from the clamp inner frames 23 and 24 during molding. Besides, in this case, the ridge line 34 is used instead of the point clamping by the tip of the screw 18 shown in FIG. 4 as a conventional example.
Since a plurality of lines are sandwiched by the above, the sheet-shaped material 1 does not wavy inside the clamp inner frames 23 and 24 during molding, and the airtight does not become insufficient.

Further, when the sheet-shaped material 1 has a poor molding elongation and is a laminate of the fibrous material 15 and the thermoplastic base material sheet 16 which are cut under the molding conditions, the meshing pressure of the clamp inner frames 23 and 24 is set at each stage of molding. Since the sheet-shaped material 1 can be displaced inwardly inward of the clamp inner frames 23, 24 according to the degree of expansion by changing with, the deep-formed molded product can be manufactured without cutting the fibrous material 15. be able to.

Embodiments Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 6 is a partial sectional perspective view of the upper and lower clamp inner frames 23, 24 of the present invention.
Are separated from the mold 2 as shown in FIG. 5 and are located outside thereof. The clamp inner frames 23 and 24 have a plurality of steel plates 23a to 23d and 24a to 24d having different widths, respectively.
, Which are integrally connected by a bolt 30 and a nut 31 (FIG. 7). The thickness of each steel plate is about 3 to 20 mm, and the thicknesses of the steel plates at positions corresponding to each other in the vertical direction are almost the same. The number of steel plates in the assembly is 2
Through 10. The width of each steel plate is 10 to 80 mm, and the total widths of the steel plates at the vertically corresponding positions are substantially the same. Therefore, as shown in FIG. 6, when the end faces of the steel plates of one of the clamp inner frames are aligned and gathered into one plane, a plurality of terraces 22 are formed on each sandwiching face 21. The difference in width between adjacent steel plates in the assembly, that is, the step difference is generally in the range of 1 to 20 mm, and is generally substantially constant. Therefore, the plane connecting the ridge lines of the adjacent steel plates on the side of the holding surface 21 is the clamp inner frames 23, 2
It is inclined at 45 to 80 ° with respect to the sandwiching direction of No. 4. Thus, the sandwiching surfaces 21 of the upper and lower clamp frames 23 and 24 that sandwich the thermoforming sheet material 1 are formed with terraces 22 whose heights change inward and outward.

Since a plurality of terraces 22 are provided on the sandwiching surfaces 22 of the upper and lower clamp inner frames 23, 24, the clamp inner frames 23, 24
When the sheet-shaped material 1 is sandwiched by narrowing the gaps, the terraces 22 are meshed with each other while sandwiching the sheet-shaped material 1 by the respective ridge lines 34 as shown in FIG. The gripping force of the sheet-shaped material 1 due to the meshing differs from the pressure at which the meshing is performed.

When the clamp inner frames 23 and 24 have a function of changing the meshing pressure, the sheet-shaped material 1 contacts the molding die 2,
When the sheet material 1 is stretched, depending on the stretch,
The meshing pressure is slightly reduced to allow the sheet-shaped material 1 to shift to the inside of the clamp inner frames 23, 24 by a necessary amount, and then the meshing pressure is increased again. By this operation, the sheet-shaped material 1 has a poor molding elongation and the expansion rate is large under the molding conditions, so the fiber material 15 to be cut and the thermoplastic base material sheet 16
Even if it is a laminated body of, the fibrous material 15 can be molded without being cut. Further, as in the case of the system in which the sheet-shaped material 1 freely slides into the clamp inner frames 23, 24, the extra sheet-shaped material 1 is slackened due to the inward movement and leaves wrinkles on the fiber material 15 after molding. There is no.

As another embodiment, the clamping surfaces of the clamp inner frames 23, 24 are composed of terraces that descend toward the outside of the clamp inner frames 41, 42 as shown in FIG. 8 (a), and in FIG. 8 (b). As shown in FIG. 8 (c), the clamp inner frames 43, 44 are provided with the highest or lowest terraces in the central portion in the thickness direction. is there.

Further, the ridge line of the sandwiching surface of any one side of the clamp inner frame composed of four sides is chamfered in an arc shape to make it relatively easy to move the sheet-shaped material 1 into the clamp inner frame on that side.
It can be used to mold products with different vertical and horizontal expansion rates. Further, the same effect can be obtained by changing the thickness and width of the steel plate.

Effect of the Invention Since the terraces that mesh with each other are provided on the clamping surface of the clamp inner frame that clamps the sheet material to be molded, the following effects are achieved.

The sheet-shaped material can be firmly sandwiched between the ridgelines of the terraces. It is particularly advantageous if the sheet material comprises a fibrous material with poor molding elongation.

Further, since the clamping force of the inner frame of the clamp is strong, the clamping area can be reduced as compared with the conventional clamping method, and the sheet material to be molded can be saved.

If the sheet material has poor molding elongation and contains fiber material that can be cut under the molding conditions, the pressure at which the clamp inner frame engages is slightly reduced during molding to clamp only the required amount of sheet material. It is possible to allow a displacement movement inside the inner frame.

The ridgeline on any side of the clamp inner frame is chamfered in an arc shape to make it easier to move the sheet-shaped material 1 inside the clamp inner frame on that side than the other sides, and It can be used to mold different products.

[Brief description of drawings]

1 and 2 are explanatory cross-sectional views showing a clamp inner frame when thermoforming a sheet-shaped material, and FIGS. 3 and 4 are cross-sectional views showing a sandwiching surface of a conventional clamp inner frame. FIG. 6 is a sectional view showing an example of the inner frame of the clamp of the present invention, and FIG.
FIG. 7 is an enlarged perspective view of only the clamp inner frame, FIG. 7 is an enlarged cross-sectional view of the clamp inner frame of FIG. 5, and FIGS. 8A to 8C each show another embodiment of the clamp inner frame. FIG. DESCRIPTION OF SYMBOLS 1 ... Sheet-shaped material, 2 ... Mold 21 ... Clamping surface, 22 ... Terraces 23, 24, 41, 42, 43, 44, 45, 46 ... Clamp inner frame

Claims (1)

[Scope of utility model registration request] 1. A holding surface of a pair of upper and lower clamp inner frames which are separated from a molding die and are located outside thereof and which sandwich a thermoforming sheet-shaped material, has heights in the inner and outer directions of the clamp inner frames. A clamp inner frame for sandwiching a thermoforming sheet-shaped material, characterized in that terraces that change and mesh with each other are provided.