DE7506114U - DEVICE FOR DEEP-DRAWING OF PLASTIC FILMS HELD IN A CLAMPING FRAME AND WARMED WITH THIS - Google Patents

Description

Daimler-Benz Aktiengesellschaft Stuttgart-Untertürkheim

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Pain Io 5βΐ / 4 2/24/75

Device for deep drawing of plastic films held in a tenter frame and heated with them

The invention relates to a device for deep drawing held in and with a tenter frame heated plastic films or plastic plates on a Model form by vacuum deformation which in warn state are pla & ic deformable and after they have cooled down a form a stiff shell, which in a further work step, supported in a foaming tool, for foaming a foam layer that connects to the shell mold is used.

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Plastic molded shells of this type, which are provided with a foam layer on their inside, are used, for example cover the cardan tunnel in a motor vehicle and establish a connection to the dashboard, where openings for a radio, heating or ventilation control lever or the like are provided in the shell mold are.

During vacuum forming according to the previously conventional process the foils are clamped in one plane and heated to such an extent that they are plastically deformed over a model can be deformed there and, after they have cooled down, have taken on the shape of the model »Created here very often large degrees of deformation leading to thin spots in the thermoplastic material and also often to surface structure distortions because of the plastic material used according to its intended use was provided with grains or other embellishments. In addition, the material to be deformed tended to wrinkle easily. In our patent application P 2% 18 445.ο (Daim Io 126) is now described how model shapes are covered and can be formed that have a concave kink seen in longitudinal section and generally not without severe scar distortion or an unbearable weakening of the film pieces can be produced.

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In addition, there are sometimes narrow and high parts that have to be coated, e.g. B. storage trays, at which without further precautions the foils would have to be stretched very far in certain partial areas. Such In many cases, stretching is not permitted, as this would make the film extremely thin and would without any scarring. For example, there are very deep parts with a development of over 100 millimeters. the The foil width used is only 52o millimeters. With parts like this, it would apply at certain points an excerpt of the film width of over 100 percent. Ways must therefore be found, this oversized excerpt to restrict the film in certain places.

The object of the invention is to create a device with which even very deep, narrow parts can be deep drawn without allowing the foil thickness in certain places to stretch a lot and to keep the stretching within reasonable limits.

This object is achieved by the invention in that Parts of the clamping frame compared to other parts of the same

of a cubic table

are displaceable and thereby assume a position dependent on one another or on the central axis of the stroke position / position. The displaceable parts can be spars of the clamping frame, which can be displaced parallel to the longitudinal axis of the model shape is arranged. For this purpose, the spars of the clamping frame expediently have guide blocks at their two ends

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on, the leadership on the transverse parts of the frame • ten slide.

On the bars themselves, buk clamping of the plastic can be done · » Foil clamping pieces can be arranged, which are connected to the spars move together. In addition, the clamping pieces can be provided with hinges, which - the shape of the model shape adapted - near a depression of the model form.

When the model form is pushed into the area of the clamping frame by lifting the lifting table, the bars must now of the clamping frame in a very specific manner depending on the respective lifting height of the lifting table against each other on the Center of the model shape to be guided. Curved pieces are attached to the lifting table for this purpose. Place against these curved pieces bolts attached to the spars or their guide blocks and these bolts are attached to the Curved pieces pressed so that when lifting and lowering the lifting table, the bars move together or apart.

This means that when the lifting table is lowered after the film has cooled down the model form can be moved down again from the film form molded by it after it has cooled down can, it is necessary that at least in the initial area of the lowering of the lifting table parts of the curve segments initially run parallel to the lowering direction or the bars are initially held so that they press outwards wanting feathers do not initially take effect. You can do this

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advantageous the spars or guide block on the guide rod f ge be clamped. After a predetermined lowering section, | namely when the deformed film has been freed from the model shape the clamping can be released again, so that I

ψ, then unfold the bars again. I.

The bars can also necessarily be guided when raising and lowering the lifting table. Then be in further development of the invention on the lifting table curved pieces brought and these are designed so that they are in recesses | the guide block engaging this when lifting and lowering- ',

push together or move apart. t

The invention is based on a shown in the drawing \

Embodiments in the following description in more detail erläu- \ t, which also further details of the subject matter of the inventions <■

can be obtained. It show p

1 shows a perspective view of a clamping frame I

and underneath a lowered lifting table with a |

model shape lying on top with partly large deep ■ ( drawing height,

2 shows the top view of the clamping frame,

* Fig. 3 is a schematic representation of a view of the;

Tenter frame in the direction of arrow III in Fig. 2 f

when the lifting table is raised on which the model §

shape and with clamping pieces moved to the center,

Fig. K shows a schematic representation of a view of a

Clamping frame, the clamping pieces of which cannot be brought together, with the lifting table raised, on the ' the model shape is located.

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In a line A indicated by a dash-dotted line in FIG Heating wire 2 are located above the deep drawing device 1, which in its entirety have a radiator home for heating the ones to be clamped in the clamping frame and deep-drawing

Form kunatof film 3. The plastic film has a shape

(Dimension d in Fig. 3a) overall width of 52o millimeters / and is used to expand deeply

in Fig. 3 «their two edges with a width of So millimeters (MaS f / each clamped between clamping pieces 4 attached to HoI-MB 5 de · clamping frame · 6 articulated aind. The spars 5 point Guide blocks 7 open on theirs The guide rods 8 forming the transverse parts of the clamping frame 6 can slide. Under the tensioning frame 6 there is also the up and down mobile lifting table 9, on which the model form 11 is placed in FIG. 1.

On both sides of the lifting table 9 aind two curved pieces 12 are attached, which protrude upwards and on the curved surfaces 13 of which are arranged on the guide block 7 bolts Ik . These bolts rest on the curved surfaces 13 of the curved pieces 12 that on the guide

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support rods 8 between the guide block 7 springs / arranged aind, which press the bars 5 apart.

When the lifting table is raised and lowered, the helmets can also be controlled by the fact that the curve parts engage in the slots 16 dw guide block 7. These curve pieces are then designed so that accordingly

7506114 07/06/78

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formed curved surfaces when lifting dea Hubtiachea 9 slide along the inner surfaces 17 and thereby lead the Holne 5 to the center, while when lowering dea
Hubtiache · correspondingly designed curve pieces slide along the outer surfaces 18 and thereby bring the bars 5 out again.

So that when lowering the lifting table on a predetermined path, the bars 5 initially remain in their middle position until the model shape has been pulled down from the film, which has meanwhile been molded on,
the guide block 7 can be provided with clamping screws 19 with which the spars 5 are initially held in their central position on the predetermined path
and are only released after this distance has been covered, so that they are pushed apart again under the pressure of the spring 15, bia the bolts Xk rest on the curved surfaces 13 of the curved pieces 12.

By comparing the shown in Fig. K with that,

in Fig. 3 shows that the film in "lets by using the device according to the invention we

needs to be stretched significantly less and moreover

by application of the invention a significant waste, the would arise without the application of the same, does not arise.

In Fig. 4, a rigid clamping frame is shown.

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The Kleame-tieke 4 'are therefore not movable. The restrained • Plastic 3 ■ * · * ■ a string width of 52o millimeters Ib the atarren clamping piece 4 ao is clamped, that there is an edge of 20 millimeters on each The side is jammed. Then the model form «11 ▼ on from below into the heated film, so that the film 3 is separated from the two Klearn pieces / over the hy-

potenusenabsehnitte c * and the roof surface 21 of the model form 11 extends. Then the vacuum is switched on, so that the sections c * of the film lie against the surfaces a ¹ and b * and thus stretch. With regard to the Pythagorean theorem, it is clear that the total length of the film section, which is composed of sections a 'and b *, is greater than section c * before the stretching. In addition, the rigid clamping frame according to FIG. 4 has the disadvantage that the section y is omitted as waste on both sides.

In the embodiment according to the invention according to FIG. 3, however is saved by moving the clamping pieces 4 film material, because the Klemaiatüeke by the amount "ac" be retracted and therefore the sections χ on both sides do not arise as waste. Again, the Plastic film 3 with an original width of 52o millimeters Clamped into the clamping pieces 4 on both sides with 20 millimeters. While the lifting table is moving up 9 move the clamping pieces 4 from the position shown in dashed lines in FIG. 3 into the position drawn out in the figure below shown location of the same. The heated foil

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The model forum 11 starts up between the in Fig. 3 stretched Klearnstticken shown 4 stretched and excited, like in Pig. 3 is shown, then the vacuum is switched on, so that the sections c of the foil to the model shape and now the sections a and b form. It can easily be seen from the drawing that the film is now much less stretched than in the case of FIG. 4. The sum of the sections a and b is not even as long as the pre-stretched section c 'and this is - as already said - significantly smaller than the sum of the sections a 'and b'.

In Fig. 1 and 2, the clamping pieces 4 are hinged shown, which are articulated to the spars with a joint 22. The joint is located in the area of the depression 23 of the model form 11 so that the film can more easily adapt to this depression. The two legs the clamping piece «4 are when the lifting table is raised 9 raised by the shoulder 24, against which the clamping pieces apply.

In the case of model forms without such depressions, the Clamping pieces of course fixedly arranged on the bars 5 or integrated with them »a. .

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Claims (6)

MM I ·· Oil · · ··· Dai * Iq 5βΐΛ Anaprttcha 1 "Device for" deep drawing of held in a "stenter frame and "it dieeae" heated plastic films or Kunatatoff plates on a model form "by vacuum forming, which in warn «Znatand plaatiach verforabar aind and, after cooling down, form a mature foraachale, which is supported in a further work cycle a show tool, used to open a show that connects the foraachaleβ is, characterized in that parts (5) dea Spannrahaena (6) compared to others Parts (8) can be displaced in the same way and thereby a position which is dependent on the stroke position of the model fora (ll) from each other or from the longitudinal side telachae (L) the model for «occupy. 2. Device according to Anapruch 1, characterized that the displaceable parts Holae (5) dea. Spannrahnena (6) aind, which are parallel to Längaittelachae (L) der Modellfor «(ll) displaceable arranged aind. 3 «device according to Anapruch 1 or 2, characterized in that the Holae (5) dea Spannrahaena (6) have guide blocks (7) at both ends, which are attached to the transverse parts of the hooks (6) Forming FUhrungaatangen (8) slide. 7506114 07/06/78 ■ I I III » Il II * II · ■ ' I «With · ··· - 11 - Daim Io 5βΐ / 4 4. Device according to claims 1 to 3, characterized in that on the spars (5) Clamping pieces (4) for clamping the plastic film (3) are arranged, which are together with the spars (5) shift. 5. Device according to claims 1 to 4, characterized in that the clamping pieces (4) are provided with hinges (22) which - adapted to the shape of the model shape (ll) - in the vicinity of a depression (23) of the model shape ( ll) are located. 6. Device according to claims 1 to 5 »thereby characterized in that the springs (15) apart the bars (5) and on them or on the guide block (7) arranged bolts (14) against the lifting ·, Table (9) press provided curve pieces (12) so that I when lifting and lowering the lifting device (9) the bars (5) I move together or apart. : | 7. Device according to claim 6, characterized in that - Ί indicates that the bars (5) or guide I rungskloben (7) can be clamped to the guide rods (8) j »ind. ■ a 8. Device according to claims 1 to 7, characterized I marked that on the lifting table (9) I attached curved pieces (12) and designed them in this way § are that they are in slots (l6) of the guide kioeben (7) I intervening when raising and lowering the lift table Press the I shes (9) together or move them apart. 7506114 07/06/78