The present disclosure relates to a hot runner nozzle for lateral injection of plastic components. The nozzle includes a multi-part nozzle body having one or more tip elements which protrude outwardly over a circumferential area of the nozzle body.
WO 99/37 461 A1, US 2002/0098262 and EP 0186 413 A2 are representative of the technological background.
It is often advantageous in the field of injection molding for plastic to perform injection for plastic parts laterally, that is perpendicularly or obliquely in relation to the demolding direction. For this purpose, so-called hot runner nozzles for lateral injection are used, which are also known as lateral injection nozzles and which comprise a nozzle body and tip elements. In order to achieve good temperature control for the melt up to the surface of the article, the nozzle tips or tip elements must be guided up to the surface of the article.
It is further known to divide the mold components, or the die components, which enclose the nozzle body, so that the nozzle tips or the nozzle body can be mounted in the case of multi-cavity arrangements. Such a state of the art is shown in DE 100 08 471 A1. The division is disadvantageous because a complex construction of the die needs to ensure the necessary retaining forces in order to prevent leakages.
That is why constructions of lateral injection nozzles with tip elements appear to be advantageous which allow using non-divisible inserts. This can occur for example with adjustable tip elements, as proposed in DE 197 42 099 A1, or with the help of subsequent mounting of the tips in an integral nozzle body once the nozzle body has been mounted (see EP 1524091A2 and DE 103 45 578 A1, for example). In the case of the tip elements held in tight fit, the fit clearances are so tightly held after some time of use by the combusted plastic that destruction-free dismounting is often not possible.
The disadvantages of an adjusting mechanism are the filigree components which are partly wetted with the melt and after prolonged use no longer allow reliable adjustment or dismounting of the tips. The adjusting devices often do not permit any high force/pressure loads because they do not offer sufficient pressure surface due to the limited overall space.
The tip elements that can be mounted in the integral nozzle body on the other hand must be arranged to be very small in order to remain mountable. Moreover, the mounting/dismounting in known systems is exceptionally difficult and can often only be achieved with the destruction of the tips after prolonged use.
It is known from the generic EP 0 447 573 A1 and the priority-establishing DE 90 03 574 to arrange the nozzle body not in an integral manner but in a divided way, so that this difficulty is reduced. A holding ring is placed on a kind of base part (see FIG. 1 of EP 0 447 573 A1), on the axial side of which guide tips are held with a clamping ring. The mounting and dismounting of the tip elements is still not simple enough. Moreover, the melt flow is also not guided in a leakage-free manner from the melt entrance into the nozzle body up to the gate on the article, because the melt can also exit axially from the base part and flow about the guide tips. Considerable difficulties can occur during the dismounting of the tip elements by the ambient solidified plastic compound. The solidified plastic compound needs to be removed at first in a laborious fashion. Alternatively, the hot nozzle can be dismounted with the still doughy plastic.
The present disclosure is, therefore, based on further developing this generic state of the art, based on the concept of a divided nozzle body, in such a way that it is possible to house even relatively large tip elements in the nozzle body in a simple manner and to mount them and dismount them again after longer use in an easy manner.
The present disclosure thus relates to a hot runner nozzle for lateral injection of plastic components. The nozzle includes a multi-part nozzle body including at least one tip element which protrudes outwardly over a circumferential area of the nozzle body. The multi-part nozzle body further includes a nozzle body clamping disk section and a nozzle body base section having an axial side that has at least one recess arranged on the axial side to accommodate the at least one tip element which is pressed with the nozzle body clamping disk section against the axial side of the nozzle body base section.
The present disclosure provides for a hot runner nozzle which is arranged in such a way that the tips can be inserted easily in a multi-part nozzle body which previously has been built into a die. The chosen arrangement allows arranging the tip elements with a relatively large overall size.
US 2005/0196486 also shows an integral nozzle body with a projection integrally formed thereon.
In accordance with the present disclosure, the at least one tip of a tip element easily reaches the surface of the article to be injected. And, after a complete mounting of all components, the melt flow is guided in a leakage-free manner from the melt entrance to the nozzle body up to the gating on the article.
Relatively large retaining forces can be realized by the arrangement, according to the present disclosure, of the nozzle body, so that high tightness can be achieved.
After the mounting of the tip inserts, the sealing sleeves rest on the wall of the die insert, according to an embodiment of the present disclosure. Or, they are spaced to such an extent that, after reaching the operating temperature, there is sufficient surface pressing between the sealing sleeve and the wall of the die insert by thermal expansion of the overall nozzle.
Other aspects of the present disclosure will become apparent from the following descriptions when considered in conjunction with the accompanying drawings.
a to e show the dismounting of a nozzle body and a tip insert in five subsequent steps, according to the present disclosure.
a shows a partial sectional perspective view through a partial area of a die with a tip insert according to
b shows an enlarged view of a section of
As suggested in
The disclosure herein shall be understood to be exemplary and not in any limiting manner regarding, among other things, the description of the position of only one or, at other locations, several of the tip elements 3, 3′. Terms such as “upper” or “bottom” shall not be understood to be limiting, but merely relate to the respective arrangement and alignment in the Figures.
On an opposite axial side, which is considered to be the upper axial side in
The partial channels 25c are in alignment with entrance openings 12a of melt, or guide, channels 12 in the tip elements 3 which are inserted in the recesses 14.
The tip elements 3 (see
Tip inserts 37 are arranged in such a way that after an insertion in the recesses 5, 14, they are partly enclosed, for example, half enclosed, and rest with a base body 19 in their area facing away from the tip 1. This occurs with an oblique surface 8 in reverse against an oblique surface 11 and on a side facing the actual tip 1 via a shoulder 15 on a respective surface 16 of the recess 14 (see
The guide channels 12 each comprise an outlet opening 12b into an annular gating recess 32 which encloses the nozzle tip 1 (see
The multi-part nozzle body comprises the nozzle body clamping disk section 6 in addition to the nozzle body base section 2, which clamping disk section 6 is provided on its axial side facing towards the nozzle body base section 2 with a circumferential edge 28. Circumferential edge 28 comprises a central recess 17, with the edge 28 being provided with radially aligned recesses 7 on the axial side provided in the mounted state relative to the recesses 5, 14 of the nozzle body 2, in which the tip inserts 37 engage and which are opposite of the recesses 14 in the mounted state.
The nozzle body clamping disk section 6 downwardly delimits the area in cooperation with the sealing sleeve 4 through which the melt flows when passing through the nozzle body and stabilizes the sealing sleeve 4 on its circumference.
The nozzle body clamping disk section 6 is held in a simple manner on the nozzle body base section 2 in a simple manner by at least one or several fastening screws 9, 10. The screws 9, 10 penetrate bore holes of the nozzle body clamping disk section 6 and are screwed into threaded bores 29 of the nozzle body from its axial side.
It is within the scope of the present disclosure to provide only one single fastening screw 10, for example, a fastening screw 10 which extends in the central longitudinal axis of the nozzle body base section 2 and which is dimensioned accordingly. The effect of this fastening screw 10 can be supported by one or several fastening screws 9 which are, for example, arranged on a concentric circle about the central fastening screw 10 and which can also be dimensioned smaller than the middle fastening screw 10.
The nozzle body clamping disk section 6 is aligned axially to the nozzle body base section 2. The nozzle body disk section 6 comprising a recess 17 that fixes the tip elements 3 in an interlocking and frictional way on the nozzle body base section 2 in such a way that the sealing surface 8 of the nozzle element 3 rests in a sealing manner on the surface 11 of the nozzle body 2 with high surface pressing.
The nozzle tips 1 protrude radially outwardly beyond the outer circumference of the nozzle body clamping disk section 6 and the nozzle body base section 2.
Without the nozzle body clamping disk section 6, the tip elements 3 would not be held on the nozzle body base section 2 and the melt path into the tool would not be complete.
In the mounted state, each tip element 3, 3′ rests with a radially outwardly facing shoulder 15 on the respective surface 16 of the recess 14 of the nozzle body 2.
The nozzle body base section 2 is enclosed by at least one heating element 20 on its side facing away from the axial side with the recesses 5, 14. The heating element 20 is enclosed by an outer sleeve 21 which carries a secondary sealing collar 23. A support and centering ring 22 fixes the heating element 20 and the sleeve 21 and is fixed in an interlocking manner, for example, with a thread, to the nozzle body base section 2.
The nozzle body clamping disk section 6 also carries a secondary sealing collar 24.
The tip 1 is configured and arranged in such a way that in the mounted state it reaches the surface of an article 30 to be injected. After a complete mounting of all parts, the melt flow is guided in a leakage-free manner from the melt entrance 31 up to the gate 36 on the article 30.
The nozzle body base section 2 is arranged in such a way that one or several tip inserts 37, which includes tip element 3 and the sealing sleeve 4 mounted thereon, can be inserted into the respective recesses 5, 14 on the nozzle body base section 2 in such a way that tip 1 will reach a surface of the article 30 (see
The recesses 5 on the nozzle body base section 6 partly encompass the tip insert 37 only partly as shown, for example, only up to half the height (see
It is the mounting of the nozzle body clamping disk section 6 in which corresponding recesses 7 are present that will fix the tip inserts 37.
After the mounting of the tip inserts 37, the sealing sleeves 4 rest on a wall 34 of die insert 33, or they are spaced to such an extent that after reaching the operating temperature as a result of the thermal expansion of the entire nozzle, a sufficient surface pressing is obtained between the sealing sleeve 4 and the wall 34 of the die insert 33. The sealing sleeve 4 rests over a portion of its axial length on a cylindrical shoulder 38 of the tip element 3 which is adjacent to the base body 19 (see
It is within the scope of the present disclosure to produce or arrange at least one tip insert 37 in an integral manner. That is, the tip element 3 with the sealing sleeve 4.
The rear-side contact surface 8 of the tip element 3 is arranged under a certain angle α, for example, at an acute angle relative to the axial direction X (see
The arrangement of the angle α leads to the consequence that, as a result of the introduced axial screw forces, a high surface pressing is obtained between the rear-side area 8 of the tip element 3 and the respective counter-surface 11 of the nozzle body base section 2.
This is necessary because the melt channel 12 to the tip elements 3 is connected via this surface with the partial channel 25 and thus the tightness or freedom from leakages between the melt channel 12 and the partial channel 25c is ensured. As a result, the melt channel 12 is a tight channel from the melt channel or area 25 up to the gate 36.
In order to ensure that the axial force can act upon the tip elements 3 in an unrestricted way, the nozzle body clamping disk section 6 must be arranged in such a way that it only presses on the tip elements 3. Furthermore, the tip elements 3 must be able to rest with their shoulder 15 on the surface 16 of the nozzle body base section 2. The tip elements 3 may rest on surface 18 (see
As a result of the thermal expansion of the entire lateral injection nozzles, the sealing sleeves 4 are pressed against the die wall 34. This produces the sealing effect between the melt channel 12 of the tip element 3 and the gating recess 32 in the die insert 33.
Although the reaction force between the sealing sleeves 4 and the die wall 34 relieves the tensioning situation between the tip elements 3 and the two-part nozzle body base section and clasping disk section 2, 6, respectively, the sealing force on the rear side of the tip element 3, that is, the melt channel transition from the nozzle body 2, is thus not relieved. On the contrary, the surface pressing is usually even increased.
As is shown in
It is advantageous, according to the embodiment shown in
The actuating contour can, within the scope of the present disclosure, alternatively be an actuating projection or an actuating recess (not shown) which allows the application of a lever element (not shown).
It is important that at first the clamped angular surfaces can be separated by the lever arrangement, so that the bonding of forces is detached. The detached tip inserts 37 can be dismounted by turning and displacing the same.
Whereas the embodiments discussed above each show a lateral injection in the horizontal direction, which means at an angle of 90° in relation to the main opening direction X of the hot runner nozzle, it is, within the scope of the present disclosure, by the advantageous pivoting mounting of the tip inserts 37′ to realize a further injection angle γ beyond a standard angle of 90° in lateral injection, which further injection angle can reach from 45° up to 0° for example, with γ=90° describing the radially outwardly extending direction and γ=0° describing the direction perpendicularly downwardly, which corresponds in this case to the axial direction X or the mounting direction X.
The pivoting installation or detachment of the tip inserts 37′ also allows achieving undercut tab geometries (see
The tip inserts 37′ remain aligned perpendicularly to the axial direction X with their “main axis” and only the actual conical tip 1′ itself is arranged at the required angle α, e.g. γ=30°, 45° or 0°, bent in relation to the axial direction/mounting direction X with reference to the nozzle body clamping disk section 6 (see
The “horizontal” main axis, for example, 90° to the direction X of the tip inserts 37′ is advantageous because in this way the sealing sleeve 4 still rests horizontally on the nozzle body base section 2 as a result of thermal expansion, as described above in connection with
In accordance with the embodiments of
The cylindrical area 1a′ protrudes outwardly in the mounted state on the nozzle body over the circumferential edge of the nozzle body base section 2 and the tip area 1b′ is aligned obliquely in relation to the axis of the cylindrical area.
As is shown in
The bent region of tips 1′ may undercut the contour of the gating recess 32 of the die because the respective counter-contours of the mold can be circumvented as a result of the swiveling in during mounting.
As a result, articles such as disposable syringes can be injected at the handle part under 0° (see
Embodiments of hot runner nozzles with such tip inserts are shown in
Although the present disclosure has been described and illustrated in detail, it is to be clearly understood that this is done by way of illustration and example only and is not to be taken by way of limitation. The scope of the present disclosure is to be limited only by the terms of the appended claims.
Number | Date | Country | Kind |
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202008005073.1 | Apr 2008 | DE | national |
202008013086.7 | Oct 2008 | DE | national |
This application is a national stage of International Application PCT/EP2009/053866, filed Apr. 1, 2009 and claims benefit of and priority to German Patent Application Nos. 20 2008 005 073.1 filed Apr. 11, 2008, and 20 2008 013 086.7, filed Oct. 1, 2008, the content of which Applications are incorporated by reference herein.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2009/053866 | 4/1/2009 | WO | 00 | 10/7/2010 |