DE9018012U1 - Casting mold for producing shaped workpieces - Google Patents

Description

Gbm branch from P 40 41 330.6
Marianne WIESER

New description

Casting mold for the production of molded workpieces

The invention relates to a casting mold according to the preamble of claim 1.

In particular, for the injection molding process, there are already molds whose cavity can be modified by using inserts in such a way that, for example, workpieces of one and the same basic shape can always be produced with such a mold, although different shapes can be created in certain areas of the workpiece depending on the intended use. For example, one and the same basic mold can be used in the injection molding process to produce housings for different television sets which essentially have to have the same basic shape but differ in details, which therefore have to have recesses in different places depending on the model of the television set, for example ¹ .

In order to create such recesses, inserts corresponding to the shape of the desired recess must be placed in the mold cavity of a corresponding injection mold.

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To date, inserts have been fitted by drilling holes in the molds from the outside and then screwing the insert into place using a screw inserted through the hole from the outside. For example, DE-OS 22 55 045 shows a two-part die-casting mold, the anvil of which is attached to the mold using screw bolts that can be operated from the outside of the mold.

With such a procedure, the shape of the insert, which determines the shape of the workpiece, remains unaffected, but on the other hand the holes made from the outside of the mold cause undesirable construction work and set-up times and may also interfere with the installation of tempering channels and the like.

If a central screw is screwed into a round mold insert from the outside, vibrations can cause the insert to become undesirably loose.

From GB-A 22 29 670, which forms the basis of the preamble of claim 1, an injection mold is already known in which a mold insert is attached to a mold base on the side of the separating surface between the mold halves by means of a

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screw is attached, the screw slot of which is exposed and which is screwed into the inner wall of the lower part of the mold from the inside of the mold. The insert protrudes from the parting surface and lies flush against it. It serves as a closing piece for a mold channel in the other half of the mold and also works together with this channel as a shearing element.

DE-GM-82 33 634 shows a so-called identification insert, which can be inserted into the injection molding tool and is recessed into the mold wall for marking workpieces that can be manufactured using the injection molding process. A threaded hole is provided on the inside of the injection mold into which a screw can be inserted, the head of which in turn rests in a recess in a ring that is housed in a recess in the mold wall. The screw slot is flush with the surface of the ring in the mold cavity.

The known fastenings of mold inserts from the inside of the mold explained above do indeed prevent drilling through the mold walls from the outside, which is labor-intensive and also interferes with the installation of temperature control channels and the like, as well as preventing mold production using the computer-aided CC technology, which can only be carried out from five sides.

could; however, in these known fastenings, the exposed screw heads not only cause undesirable impressions on the workpieces to be manufactured, but also such fastenings are only of limited use with regard to the various uses of casting mold inserts and also in particular with regard to their ability to be dismantled.

The present invention is based on the object of creating a casting mold of the type in question in which inserts can be easily attached and removed, in particular from the inside of the casting mold, and also in particular without disturbing the shape or construction or operation of the mold. In this case, inserts for different purposes should also be able to be attached, and in particular inserts embedded in the mold wall.

The design in question is characterized by the fact that the shape, construction and operation of the mold are not affected by the inserts, whereby the fastening screws of the inserts can also serve as a drive element not only for bringing the inserts in but also for forcibly driving them out of the mold wall. This is particularly useful for inserts that are to be attached to the inside of the mold, but

also for inserts that are attached to the outside or back of molds as centering and fixing elements, for example. The claimed design is also useful for multi-tier molds and also for particularly thick mold plates that then do not need to be completely drilled through.

The mold according to the invention, with its removable inserts, can thus be used favorably to achieve different shapes in certain areas of otherwise identical molded workpieces, or different construction elements of the molds themselves, such as guide pieces, locks, diagonal pull elements, pressure pieces with a secure fit and simple and quick assembly and disassembly, can also be provided.

Molds according to the present invention are also particularly advantageous in connection with CC technology, i.e. computer-aided mold making, in which mold plates can only be economically processed from five sides, while processing from the back cannot be carried out economically. The inserts that can be attached from the front according to the present invention are particularly advantageous for this application.

* 4

The subclaims identify advantageous embodiments and further developments of the basic principle defined in the main claim.

The following is a description of embodiments of the invention with reference to drawings.

™ Fig. 1 shows an insert installed in a mold half (with fixing pin for a holding body of the fastening screw),

Fig. 2 shows an insert corresponding to Fig. 1, but removed from the mold half (and with a thread for fixing the holding body),

Fig. 3 shows a mold consisting of two mold halves (mold plates) J± with several built-in inserts,

Fig. 4 shows a diagram of a molded workpiece to be cast using the mold shown in Fig. 3.

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Fig. 1 shows an overall insert for casting molds (pad) 7β&ogr;;&iacgr;&ogr;9<, with which molds can be produced.

Such a molded part is shown in its entirety in Fig. 4. Such a molded part can be made from castable and sprayable materials, and in particular from metals and plastics. Such molded parts are used in a variety of designs as structural parts, housings, etc. in the most diverse areas of technology, and it is necessary to design such molded parts not only as uniform plates, angle pieces, hollow bodies, etc., but also to provide attachments and recesses on such molded parts, as shown in Fig. 4 at 1, 3 and 5.

.In Fig. 3 you can see a casting mold by means of which a mold can be produced in the design shown in Fig. 4. The areas of the mold corresponding to the recesses 1, 3 and 5 of the mold are designated 1', 3' and ⁵ ', both areas 1', 3' and 5' are thus components of the mold cavity to be poured, and in order for these recesses to be produced, corresponding inserts 1", 3" and 5" must be provided in the mold cavity.

In a manner to be described in more detail, the casting mold shown in Fig. 3 also has other inserts 7, 9, 11, which serve to guide the elements of the mold in a manner to be described in more detail.

¹ The present invention relates to the fastening of inserts of the type in question to the inner wall of the foriti cavity, and Fig. 1 and 2 illustrate two examples of such inserts, which are, for example,

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*· may be the type of insert shown at 5" in Fig. 3 for producing a recess in a workpiece.

B The insert shown in Fig. 1 has a molded part 13*, the shape of which corresponds to the shape to be produced on the workpiece. In Fig. 1, the inner wall of the mold cavity of the casting mold is indicated at 15 and the molded part 13 is let into a corresponding recess 17 in this inner wall. The molded part can also have a slight bevel 19.

The molded part 13 of the insert ¹ is fastened to the inner wall 15 by means of a fastening screw 21 which is screwed into the inner wall 21 from the inside of the mold. The fastening screw 21 sits with its head 23 in a cavity 25 of the insert. The cavity 25 of the insert can be reached from the side of the mold cavity via an access hole 27 which can be closed with a lens-head screw ^^ having a cap 29. The cavity 25 of the insert 7 in which the fastening screw 21 sits has a shoulder 33 on the side of the access hole 27 on which the grip area of the fastening screw provided with a screw slot 35 can rest in a seal against the mold cavity. In the direction of the wall 15 of the form hi, the screw head 23 is supported by means of a curved holding body 37, which in turn is supported on a shoulder 39 of the cavity 25. The dimensions of the cavity 25, the curved surface ³ of the screw head 23 and the arrangement of the shoulders 39 are such that the screw head is freely rotatable between the shoulder 33 of the cavity and an inclined shoulder 41 of the holding body.

The front surface 45 of the square-shaped Maltekötpet located on the side of the floor wall is flush with the front surface 47 of the shaped piece^3 of the insert^=·

In the embodiment shown in Fig. 1, a fixing pin 49 inserted from the side serves to produce a force-fitting connection between the molded part 13 of the insert Sv and the ring-shaped retaining body 37.

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To attach the insert to the inner wall 15 of the mold, the fastening screw 21 is first connected to the insert in a loosely rotatable manner using the ring-shaped retaining cap 37, and the fastening screw 21 can then be loosely tightened using a screwdriver.

through the access hole 27 (not yet closed by the £, /? Linsenktipfj(^3i) fcdbStigt: It can therefore

For example, a narrow screwdriver can be inserted through the access hole 2$- and then the fastening screw 21 can be screwed into the thread 51 of the inner wall of the mold until the molded part 13 is completely pulled into the recess 17. The fastening screw 21 can also _be conveniently equipped with a hexagon socket instead of a screw wrench so that a hexagon wrench is then used as a screwdriver. After the shaped piece 13 has been secured in the recess 17 in this way, the access hole 27 is closed by means of the light head cap 31. The dimensions of the light head cap are such that the light head forming the cap 29 is flush with the outer surface 53 on the circumference. This means that a recessed surface formed on a cast workpiece by means of the shaped piece 13 has a flat light head shape, as is indicated at 55 in Fig. 4.

The design of an insert described so far with reference to Fig. I corresponds essentially to the design of the insert 5" in Fig. 3. It can be seen from this that this insert is arranged with the axis of the fastening screw 59 running parallel to the direction of the mold opening. Further up in Fig. 3 you can see the insert 1", in which the fastening screw 61 is provided with the axis running transversely to the direction of the mold opening. (The direction of the mold opening is indicated in Fig. 3 by the double arrow 63 starting from the parting plane 65 of the mold).

From Fig. 3 it is also clear that the cap 29" of the screw closing the cavity of the insert has a cutting edge with respect to the mold cavity.

free closure of the cavity of the insert. In other words, the two elements 67* 69 of the " casting mold (mold halves) can be pulled together at their parting line/BTTl and the finished workpiece (Fig. 4) can be removed * without any undesirable anchoring of the workpiece by casting material flowing into the undercut cavities. Such an undercut closure of the access hole to the fastening screw of the insert

² ^ can also be achieved if, for example,

a complementarily designed insert 69 is located opposite the insert 9 shown in Fig. 3. And the facing end faces of the two inserts complement each other in a sealing manner so that the casting material has no access ■

The insert 1 ^M shown in Fig. 3, which serves to produce the recess 1 in the mold, is arranged with the axis of the fastening screw 61 transverse to the opening direction of the mold, in the case

* This insert ensures that the access hole 71 is closed without undercuts because the front side of this insert rests tightly against the wall piece 73 of the mold when the mold is closed, so that here too no casting material can penetrate into the access hole.

For this purpose, the insert 1" is seated on a slide 75 mounted on one mold half, which can be displaced in the form of the further insert 11 by means of an oblique pull element provided on the other mold half. The inserts 7 and 7 ⁽ represent T-guides, and a slide movement space is indicated at 77 in Fig. 3. If the two mold halves 67 are separated from one another in the direction of the double arrow 63, or are placed on one another

;*. &bull;/£ ₍ is moved towards each other, then the inclined element of the ^rhSphaY~s1rt~~g&ÜT±u causes a displacement of the slider 75 j~. in such a way that the slider 75 lifts the insert 1" forming the recess 1 of the workpiece upwards out of the workpiece which is still in the mold, and the tool can then be removed.* If the two mold halves are moved towards each other when closing the mold according to the double arrow 63, then the

α diagonal pull element in the form of the insert 11 the slider 75 in such a way that it performs its intended function as a release element for the recess 1 of the workpiece and can also seal the access hole 71 without undercutting by resting on the wall piece 73. The movement of the slider 75 by means of the diagonal pull element formed by the insert 11 also ensures that the access hole 79 is aligned in the required manner with the fastening screw 81 of the insert 7. The slider 75 ensures that the access hole 63 of the insert 7 is closed off.

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The described fastening of the inserts from the inside of the mold also makes it possible to provide cooling holes and tempering channels of the type indicated at 85/87 > on the mold elements, without fastening screws leading to the inserts from the outside of the mold being able to overlap with them.

Inserts mounted from the inside of the mold in the manner described above can also be designed for the attachment of a guide column 89 and corresponding guide bushing 91> or as a bridge piece like the insert 9 as well as for other purposes in which additional parts or parts that can be changed depending on the application must be mounted on the inside of a mold cavity. Thus, according to the present invention, recesses of different sizes can be created in workpieces without difficulty by simply exchanging one corresponding insert for another. The shape and size of the insert to be provided in the mold cavity are independent of the type of fastening described.

The described construction also has the advantage that the fastening screw 21 in addition to its function as a fastening element for the unit also serves as a drive

for pulling the insert into ^the recess 17 and for forcibly driving the insert out of the recess 17. This effect results from the explained support of the head of the fastening screw on the two shoulders J3 and 41.

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* The dimensions of the: "screw 21 and the lens head screw 31 can also be dimensioned in such a way that the latter, when inserted, rests on the head of the fastening screw as a counter-screw. Depending on

In this application, the lens head screw 31 can also be replaced by a plug or other non-cutting closure for the access hole 27.

Fig. 2 shows a structurally modified embodiment in which the ring-shaped mold body 37' is provided with a thread 93 instead of using a fixing pin (such as 49 in Fig. 1) for force-locking in the insert 13*, such that the head 23' of the fastening screw 23" is supported on both sides while retaining free rotation.

Using inserts of the type described above, casting molds with a high degree of variability of the mold cavity for the workpieces to be produced can be produced in a favorable manner, also with variably attached guide pieces, guide columns, etc.

Claims (1)

· Gbm branch from P 40 41 330.6 Marianne Wieser 40179 Ha/Hen New protection claims 1. Casting mold for producing molded workpieces with two mold halves and a mold cavity and at least one removable insert which is attached to one mold half by means of a fastening screw which can be moved into the fastening position by a screwdriver engaging its engagement area, the insert having a cavity for the fastening screw in which the fastening screw is supported and which is accessible to the screwdriver, characterized in that the head (23) of the fastening screw is rotatably received between two opposite shoulders (33, 41) of the insert in such a way that the insert can be driven towards or away from the wall of the casting mold by the fastening screw (25) when actuated. ,2, Casting mould according to claim 1,
characterized in that - the engagement area of the fastening screw is arranged between the separating surfaces of the mould halves and the fastening screw can be anchored in the inner wall of the mould halves, - the cavity is accessible to the screwdriver from the parting surface side and - the cavity that accommodates the fastening screw can be closed without undercuts in relation to the mold cavity. 3. Casting mold according to claim 1 or 2, characterized in that the shoulder (41) supporting the head of the fastening screw on the side of the wall of the casting mold is formed on a holding body (37) fastened in the insert (13). 4. Casting mould according to claim 3,
characterized, that the holding body is a ring (37) whose axial position is fixed in the insert by means of a force-locking connection by means of a thread, fixing pin or the like, in a detachable or non-detachable manner. 5. Casting mold according to any one of the preceding claims, characterized, · that the cavity (25) of the insert which accommodates the fastening screw can be closed by means of a cap (29) which lies flush against the front surface of the insert. 6. Casting mold according to claim 5, characterized in that the cap is formed by the head (29) of a lens-head screw. 7. Casting mould according to one or more of the preceding claims, characterized in that the insert (13) serves to produce a shape corresponding to the shape (1) of the insert on the workpiece to be cast. 8. Casting mould according to one or more of claims 1 to 7, characterized in that the insert serves to guide the mold halves. 9. Casting mold according to one or more of the preceding claims, characterized in that the insert is arranged with the axis position of the fastening screw running parallel to the opening direction of the mold. 10. Casting mold according to one or more of the preceding claims 1 to 8, characterized, that the insert is arranged with the axis of the fastening screw running transversely to the opening direction of the mold 11. Casting mould according to one or more of the preceding claims, characterized, that the insert with its front surface having the access opening of the cavity can be sealed against a counter surface by the closing movement of the mold halves. 12. Casting mould according to one or more of the preceding claims, characterized, that the insert is designed to be inserted into a recess (18) in the wall of the mould. 13. Casting mould according to claim 12,
characterized by .-·.-■ that the insert has a bevel (19) on the circumference for insertion into the recess (18) in the wall of the mold.