EP2593290A2

EP2593290A2 - Multi-part blow mould, in particular for producing plastics bottles

Info

Publication number: EP2593290A2
Application number: EP11732378.2A
Authority: EP
Inventors: Dmitrij Sokolov; Jürgen Röders
Original assignee: Roders GmbH
Current assignee: Roders GmbH
Priority date: 2010-07-12
Filing date: 2011-07-12
Publication date: 2013-05-22
Also published as: JP2013534482A; CN103298598A; WO2012007154A3; DE102010026832A1; WO2012007154A2; DE102010026832A8

Abstract

The invention relates to a multi-part blow mould for producing blown workpieces which consist of plastic, having at least one locking mechanism for detachably locking an interchangeable insert (1) in a blow mould (2), wherein the locking mechanism comprises a clamping strip (3), which is mounted on the blow mould (2) and is displaceable from a locking position into a release position, wherein the clamping strip (3) is coupled to at least one eccentric (4), which is mounted rotatably on the blow mould (2).

Description

Multi-part blow mold, in particular for the production of plastic bottles

A disadvantage of this type of attachment of the interchangeable inserts in the parent mold is that at least on one side of the parent mold at least 2 screws solved and the associated washers must be moved or rotated to perform the change of the inserts.

DE 10 2009 050 637 A1 describes a multi-part blow mold for the production of blown, made of plastic bottles. There are a variety of mechanisms explained to make a lock by means of a plurality of engagement elements. These may be formed on a common engagement body, which is displaceable in the axial direction by means of an actuating element.

The invention has for its object to provide a multi-part blow mold and in particular a quick-release system for quickly changing a replacement insert, which are quick, easy and reliable operable with a simple structure and simple, cost manufacturability.

According to the invention the object is achieved by the feature combination of claim 1, the subclaims show further advantageous embodiments of the invention.

According to the invention, it is thus provided that a multi-part blow mold for the production of blown plastic workpieces has at least one locking mechanism for releasably locking a replacement insert in a blow mold. Such inserts must be exchangeable on the one hand for reasons of wear, on the other hand for reasons of product change. For this purpose, a locking mechanism is provided according to the invention, which comprises a clamping bar, which is mounted on the blow mold and is displaceable from a locking position to a release position. The clamping bar thus serves as a bolt to lock the exchange insert or to release it for replacement. For actuation, the invention provides that the clamping bar is coupled to at least one eccentric, which is rotatably mounted on the blow mold. The invention is explained in more detail below:

According to the invention, a fastening of the interchangeable inserts is thus created in a parent mold, which allows a faster and easier operation for changing the inserts.

In order to change the exchangeable inserts, the installer only has to insert a tool, for example a hexagon wrench (Allen key), into an eccentric and turn it through 180 ° in order to loosen the exchange insert held in the nut form or to re-tighten it. For this purpose, a clamping bar, which is held and guided by means of a bridge on the web of the mother mold, pushed onto a support surface of a recess in the removable insert and holds in this way the changeover insert in the blow mold (mother mold). The clamping bar is positioned between a bearing surface of the blow mold and a bearing surface of the recess of the removable insert and the underside of the bridge under slight bias and holds in this way the replacement insert safely in the blow mold.

From the figures, which are described below, it can be seen in which position the clamping bar for changing the interchangeable inserts is and which position this occupies for holding the interchangeable inserts in the blow mold. The bearing surface for the clamping bar forms in the recess of the interchangeable insert a plane with the support for the clamping bar on the web of the blow mold, so that on the one hand the clamping bar can be pushed onto the support surface in the recess of the interchangeable insert and on the other hand the interchangeable insert safely the blow mold is held.

According to the invention, therefore, a relatively narrow tensioning strip is provided, which carries out a movement to the interchangeable insert or away from the interchangeable insert. If, as described below with reference to the embodiment, a bottle is made, which has a central axis, the clamping bar is arranged parallel to the central axis (central axis) of the bottle and thus formed by the cavity of the removable insert inner contour of the bottle. The clamping bar is thus moved radially for clamping or releasing. Since the clamping bar can be made very narrow, the narrow edge region of the blow mold (mother mold) is sufficient to store the clamping bar. Also, the mechanical drive of the clamping bar (for example, the eccentric) can be arranged according to the invention on the narrow edge of the blow mold.

According to the invention, no engagement elements are provided on the tensioning strip, in particular no additional engagement bodies or the like. Rather, the entire clamping strip is used for clamping and locking. Furthermore, the solution according to the invention is designed so that, if necessary, the replacement insert does not have to be adapted or changed. In particular, no additional recesses or the like are required in the interchangeable insert to be fastened. Thus, it is then only necessary to design the blow mold (mother mold) according to the invention and to provide it with the clamping mechanism comprising the clamping bar. This results in significant advantages, since a user can optionally continue to use the existing him interchangeable inserts easily.

It goes without saying that the tensioning strip according to the invention can also be additionally provided with locking lugs if this is necessary. In any case, however, the entire clamping bar is arranged parallel to the transition edge between the removable insert and the blow mold (mother mold) and moved (radially) in the direction of the changeover insert in the clamping direction or moved back in the opposite direction.

Due to the subsequent storage of the clamping bar, which is still described in detail below, the invention prevents these from jamming or jamming. Rather, the clamping bar according to the invention can be moved from the released position to the clamping position or back with only a single tool and with only a single handle of an operator.

It may be sufficient if the clamping system according to the invention with clamping bar, eccentric and bridge on one side (a web) of the blow mold is provided. Fixed stops can be attached to the opposite bridge which are realized for example in a conventional manner with screws and washers. If the changeover insert on one side is free, it can simply be turned out of the blow mold. For a smooth displacement of the clamping bar by the eccentric, it is advantageous if the clamping bar on the front side, which slides over the support surface of the recess of the removable insert, with a small chamfer. In a further advantageous embodiment of the invention, it is provided that the surface on the bridge at which the clamping strip is not parallel to the bearing surface of the clamping bar on the web of the blow mold and the recess of the removable insert is executed, but is slightly angled to this, so that the Clamping bar during its movement on the support surface of the recess of the removable insert a slight downward movement, in the direction of support surface of the recess of the removable insert executes. In this way, the wear of the support surface is reduced on the web of the blow mold and the recess of the interchangeable insert, since the movement of the clamping bar is no longer parallel to this under bias, but the clamping bar moves slightly onto the support surface, or it is in the Extension of the clamping bar additionally a slight clamping pressure on the replacement insert when reaching the end position of the clamping bar constructed. Before reaching the end position, the clamping bar can have a slight clearance between bridge, bridge of the blow mold and recess of the interchangeable insert. Furthermore, it is advantageous to provide a mechanical safeguard which reliably prevents the tensioning strip from "migrating" away from the support surface in the recess of the replacement insert and thus detaching the replacement insert be provided in the web of the tuyere, press from below against the clamping bar and, when the clamping bar are moved to the front position for clamping the removable insert, free directly behind the clamping bar and ensure in this way that the clamping bar only with relative great force can be shifted back over these, but in the case of an the exchange inserts with the help of the key by the power transmission of the eccentric is easily possible.

Another possibility of a simple backup is to provide instead of a backup of the clamping bar a backup of the eccentric itself, so that it can not move away by itself from the position he occupies tensioned tensioning strip away. For this purpose it is conceivable to use a spring element, e.g. a pressure ball to provide under the eccentric in the web of the blow mold, so that the eccentric is constantly pressed with a force upwards. This provides a certain "frictional engagement" which prevents twisting due to vibrations or shocks.

In addition, it may be advantageous to incorporate in the bridge a precisely fitting recess into which the eccentric is pressed from below by the spring force in the position "stretched." In this position, the precisely fitting depression in the bridge prevents twisting of the eccentric and thus keeps it In order to move the tensioning strip back out of the tensioned position with the aid of the eccentric, it is then necessary first to push the eccentric counter to the spring force of the pressure ball with the key downwards out of the precisely fitting recess so that a subsequent rotational movement becomes possible becomes.

The type of attachment according to the invention is not limited to whole interchangeable inserts. Partial inserts are used in numerous forms, e.g. to modify only the shoulder area of a bottle. Also such parts inserts can be kept in a blow mold (mother mold) according to the same principle. Only the bridge and the associated clamping bar must be made shorter in the case corresponding to the length of the part replacement insert.

Thus, it is also possible according to the invention to provide a partial replacement insert in a replacement insert in this manner. The adapter insert is fixed with a clamping strip held on the insert and the insert is in turn secured with a clamping strip whose bridge and eccentric are mounted on the web of the blow mold (nut shape). The eccentric is pressed by means of a pressure ball up and pressed in the end positions in a pocket in the bridge and is thus secured against rotation, so that vibrations can not cause the eccentric moves out of position. To rotate the eccentric, it must first be pressed down with the tool (Allen key) so that it is moved out of the secured position and can then be turned using the tool to lock or unlock the mold insert.

Advantageously, an additional guide for the slide (clamping strip) can be provided. In addition to the eccentric located in the bridge, a bridge, which runs downwards in a corresponding groove of the slider. With this system of web and groove, the slider is secured against rotation, for example, if the friction should be slightly different when moving. The system according to the invention has significant advantages over the solution described in DE 0 2009 050 637 A. The outer diameter of the interchangeable insert is determined for the individual machine types. It limits the maximum diameter of a bottle to be produced, since a certain wall thickness of the interchangeable insert between its outer radius and the inner contour for the bottle is still required in order to ensure sufficient stability for the interchangeable insert. In the solution according to the invention instead of the previous individual recesses only at the upper edge of the removable insert, a continuous elongated recess is required. In the above known solution, there are two possibilities. Either the latches must be provided on both sides of the Blasformträgers (double effort) and recesses on Blasformsegment that allow a vertical removal of the Blasformsegmentes. However, this will be difficult in practice, since the insert (the blow mold segment) in the mother mold (the blow mold carrier) usually sucks. The radii of the two parts are matched to each other with close tolerances to allow good heat transfer from the mother mold into the insert. As a result, the insert can often not straight (vertical) pull out, but it is first rotated to one side and so solved. For this purpose, however, the recesses must be circumferential in accordance with the second possibility provided in the above-mentioned document, and thus reduce the number of recesses. fend the radius of the insert (Blasformsegmentes) sensitive. This weakening of the insert reduces the feasible bottle diameter accordingly. This is a major disadvantage of the known solution. The first option is not practical, since the removal as described due to the fixed suction does not work.

In the following the invention will be described by means of embodiments in conjunction with the drawing. 1 shows a partial perspective view of a multi-part blow mold according to the invention, partly in exploded view, a partial sectional view of the quick-release system according to the invention in the closed state, a partial view, analogous to FIG. 2, in the opened state, an enlarged detail view of the embodiment, analogous to FIG enlarged detail view of the embodiment, analogous to FIG. 3, a detailed representation of the quick-release system in the closed state, a representation of the embodiment shown in FIG. 6 in the open state, and a perspective partial exploded view, analogous to FIG. 1. FIG. 1 shows a part a multi-part blow mold 2 (mother mold), in which a plurality of removable inserts 8 are receivable. Fig. 1 shows an exchange insert 1, which is suitable for producing a plastic bottle by means of a blowing process. The blow mold 2 is divided in an axial plane of symmetry that the one part of a bottle forming exchange insert 1 is visible.

Incidentally, reference is made to the prior art, for example EP 0 821 641 B1.

1 shows, according to the invention, on one side of the blow mold 2, a free space provided with a support surface 5, in which a clamping strip 3 can be inserted in a displaceable manner. The clamping strip 3 (slide) is displaceable laterally by means of an eccentric 4 and is held by means of a bridge 6, which is connected to the blow mold 2 in the region of the bearing surface 5.

The eccentric 4 has a guide pin 5 which is rotatably received in a bearing bore 16 of the bridge 6. In the region of the guide pin 15, tool engagement means 12 are provided, for example in the form of a polygonal recess, in which an external polygonal tool can be inserted.

In the bridge 6, a pocket-like recess 7 is provided, into which the eccentric can be introduced in the closed state (see FIGS. 4 and 8) in order to avoid unintentional rotation of the eccentric 4 due to vibrations during operation of the blow mold. This prevents the clamping bar 3 (slider) from slipping and unintentionally releasing or releasing the removable insert 1. The introduction of the eccentric 4 in the pocket-like recess 7 by means of an elastic element 8, which is shown in Figs. 4 and 5 only schematically as a spring. The elastic element (spring) presses a ball 17 against the underside of the eccentric 4. Alternatively, it is also possible to form the ball 17 elastic or provide another elastic element. In bridge 6, two pocket-like recesses 7 can be provided in an advantageous embodiment, in order to fix the eccentric in the positions "open" and "closed", optionally, only one recess can be provided, see above.

In order to avoid tilting of the clamping bar 3, the invention provides that it has a guide groove 10 (see in particular Fig. 8), in which a Guide web 9 of the bridge 6 engages. Thus, the clamping bar 3 can move the clamping bar 3 by rotation of the eccentric 4 about the central axis of its guide pin 15 in an opening formed in the clamping bar 3 Exzenterausnehmung 18 without them tilted. With this construction, it is possible to provide only an eccentric 4 even with a longer clamping bar 3. As a result, the handling is considerably simplified.

The guide groove 10 is preferably over the entire width of the clamping bar 3, see Fig. 1st The guide bar 9 extends over the entire width of the bridge. However, the guide bar 9 still has the additional function that the bridge 6 can be supported on the support surface 5. Optionally, in addition by the resting on the support surface 5 part of the guide web 9 still a screw can be introduced to secure the bridge 6 in the middle of the blow mold 2 (mother mold). Therefore, the guide bar 9 (see Fig. 8) is designed with two heights.

Fig. 8 further shows a space 1 1, which is formed in the bridge 6 to receive the clamping bar 3 so that it is displaceable by rotation of the eccentric 4. When screwing the bridge 6 by means of screws, which pass through mounting holes 19 of the bridge 6 and are screwed into threaded holes 20 of the blow mold 2, there is thus no risk that the clamping bar 3 is clamped.

Fig. 1 shows on the clamping bar 3 opposite side of the blow mold 2 stop means 13, which may be formed, for example in the form of screws and washer discs. This stop means 13 need not be solved for changing the exchange insert 1, but this can be turned out by loosening the clamping bar 3 (slider) to the central axis, not shown. Figs. 1 and 8 also show schematically that the clamping bar 3 may be provided at its front edge with a chamfer or rounding 14 to ensure a simpler and more reliable moving the clamping bar 3. As shown in particular in FIGS. 2, 3, 6 and 7, the invention is provided in a favorable embodiment, to provide the clamping bar 3 in cross section with a wedge-shaped profile. Accordingly, the bridge 6 may be beveled on its clamping bar 3 side facing. This results in an improved, backlash-free, secure latching or blocking of the interchangeable insert 1 in the closed state (see FIGS. 2 and 6).

2 and 3 show an embodiment in which in the clamping strip 3 securing recesses 21 are formed, in which, analogous to FIGS. 4 and 5, a ball 17 is pressed to hold the clamping bar 3 in the closed, locked state, as this results in a schematic representation of FIG. 2. This is an alternative to the use of a pocket-like recess 7 (see above). 6 and 7 show an enlarged view of the wedge-shaped design of the clamping bar 3 and their assignment to a wedge-shaped surface of the bridge. 6

LIST OF REFERENCE NUMBERS

1 change insert

2 blow mold (mother mold)

3 tensioning bar (slider)

4 eccentrics

5 contact surface

6 bridge

7 pocket-like recess

8 elastic element

9 guide bar

10 guide groove

11 free space

12 tool interventions

13 slings

14 chamfer / rounding

15 guide pins

16 bearing bore

17 ball

18 eccentric recess

19 mounting hole

20 threaded hole

21 securing recess

Claims

claims

A multi-part blow mold for the production of blown, plastic workpieces with at least one locking mechanism for releasably locking a removable insert (1) in a blow mold (2), wherein the locking mechanism comprises a clamping bar (3) which is mounted on the blow mold (2) and is displaceable from a locking position into a release position, wherein the clamping strip (3) with at least one eccentric (4) is coupled, which is rotatably mounted on the blow mold (2).

Blow mold according to claim 1, characterized in that the clamping strip (3) between a support surface (5) of the blow mold (2) and a on the blow mold (2) mounted bridge (6) is arranged.

Blow mold according to claim 1 or 2, characterized in that the eccentric (4) can be secured in a form-fitting manner, at least in the locking position.

Blow mold according to claim 2 or 3, characterized in that the eccentric (4) is resiliently biased into a pocket-like recess (7) of the bridge (6) at least in the locking position, preferably by means of an elastic element (8) acting on the eccentric (4) ), which is preferably in the region of the support surface (5) of the blow mold (2) is mounted.

Blow mold according to one of claims 1 to 4, characterized in that between the clamping bar (3) and the support surface (5) and / or the bridge (6), guide means, preferably in the form of at least one guide web (9) and / or a guide groove (0) are arranged.

Blow mold according to one of claims 1 to 5, characterized in that the clamping strip (3) is provided with a wedge-shaped cross-section.

Blow mold according to one of claims 1 to 6, characterized in that the clamping bar (3) in a free space (1 1) of the bridge (6) is arranged. Blow mold according to one of claims 1 to 7, characterized in that the eccentric (4) is provided with tool engagement means (12), preferably a polygonal recess.

Blow mold according to one of Claims 1 to 8, characterized in that a clamping strip (3) is arranged on a region of the interchangeable insert (1) and provides non-releasable stop means on a further region of the interchangeable insert (1) for exchanging the interchangeable insert (1) are. 0. blow mold according to one of claims 1 to 9, characterized in that the clamping bar (3) is rounded at least one side or provided with a chamfer (14).