DE2824729A1 - Injection mould esp. for multiple small mouldings - has heated inlet block with heat regenerator near surfaces which cool during contact with mould - Google Patents

Abstract

Injection mould with a relatively cooled mould block (20) in which the mouldings are formed operates with relative movement between these two blocks in order to make and break the communication respectively between the outlet gates of the heated inlet block and the inlet openings of the relatively cool mould block. During a portion of the time in which this communication is broken, the surfaces surrounding the outlet gates (13) are brought into contact with a gate temperature recovery block (30). Pref. the heated inlet block (10) and the relatively cool mould block (20) move relative to one another simultenously with the opening and closing movements of the mould. The formation of sprues and other waste material due to premature cooling is avoided.

Description

Injection mold

The invention relates to an injection mold with a hot mold inlet, with a hot inlet block kept at a constant high temperature, the one Has opening for the supply of molten resin, which with channels and gates communicates, a cavity block maintained at a low temperature, the contains the mold cavities with respective pouring openings for the molten resin, wherein the hot runner block and the cavity block are so movable relative to one another are that at least during the injection the gates of the hot runner block and the Pouring openings of the cavity block are placed against one another, and that after completion the gates and the pouring openings are moved apart again after the injection, and an improved injection molding process.

Enjoy injection molding processes with a hot or heated mold inlet there has recently been increasing interest from the relevant experts, because it is one of the most effective streamlining measures for the entire injection molding process enable. With this technology, unwanted by-products or sprues, which normally adhere to injection molded products can be avoided. There are a number of them of examples of practical applications of hot gate injection molding processes known.

However, the heating of the mold inlet cannot be used such Casting methods are used in which the weight ratio of the enema to the Total weight of the object or objects to be produced is relatively large is like this when making small objects or when molding at the same time a number of objects is the case. In these cases the hot inlet system takes over too large a space for the injection-molded object, so that the number of objects the simultaneous casting of several objects from a mold with a given Size can be made, is not limited by the size of the items, but on the size of the enema system, which often results in a completely inadequate Yield leads. This is contrary to the lowering of the manufacturing costs, the straight the primary objective of such hot gate injection molding processes is.

To overcome the difficulties mentioned above is the in the Fig. 1 and 2 dargestcllte form has been developed, which is a simple and therefore less is expensive in construction, and particularly for use in simultaneous injection molding small-sized objects in molding technology with hot mold inlet is determined.

In the form shown in Figs. 1 and 2, the blocks 4 and 5 of the mold in each case on a stationary die plate 2 or on a movable one Tool plate 3 of the injection molding machine attached. At blocks 5 and 4 are respectively a moving-side cavity block 20 and a stationary-side cavity block, respectively 20a are arranged in a specific relationship to one another, which will be described later. A heated gate block is comprised of a hot gate block body 10 and a spray sleeve 1 () a formed.

The hot spray sleeve 10a is attached to the block 4 and pushes with it one end to the nozzle 1 of an injection molding machine in such a way that the injection opening of the nozzle for injecting molten resin with a feed channel 11 of the hot spray sleeve The block body 10 with the heated mold inlet is a rectangular one Part whose longer side extends at right angles to the plane of the drawing and the has two parallel surfaces pointing in opposite directions. This parallel Surfaces form the door opening surfaces 15. Run into each of the door opening surfaces 15 several lines or gates 13 into it, which are arranged in a row, which runs in the longitudinal direction of the block body 10.

The gates 13 stand with the one extending in the longitudinal direction of the block body 10 Main inlet via branch lines 12c in connection, while the main inlet 12b the feeder now 11 for molten resin via the inlet channel 12a connects to the main inlet 12b.

In the block body 10 of the heated inlet and in the hot spray sleeve 10a heating elements 15 are arranged so that these parts are at a sufficient temperature to ensure a smooth flow of resin therethrough.

The movement-side cavity block 20 has two opposite one another Contact surfaces 25, which with the gate opening surfaces 15 of the block body 10 come into contact at least when the mold is closed. The movement side Cavity block 20 also has several recesses in a dividing surface 23, which form the mold cavities 21 for casting the objects to be manufactured.

Each mold cavity 21 contains an inlet port 21a for molten material Resin and parts of the cavity block 20 that are each of those formed in the block body 10 Goals 13 match.

The stationary-side cavity block 20 has two opposite one another Contact surfaces 25a on which the corresponding door opening surfaces 15 of the Move block body 10 sliding along. Between the stationary-side block 20a and a spring 6 is arranged on the block 4, which presses these two parts apart. However, the distance by which these two parts can be moved apart is through a stop 7 is limited.

In the hollow space blocks 20 and 20a there are lines or passages for cooling water so that the mold cavities are cooled to a temperature can that low is enough to solidify the resin.

In Fig. 1 the form is shown in the injection state in which the molten resin at high pressure through the nozzle of the injection molding machine into the mold is injected, while in Fig. 2 the mold is shown in the open state, by pulling the movable platen 3 of the injection molding machine around the injected Objects 40 to eject.

During the opening of the mold, i.e. in the transition period, in the the state of the mold from the closed state according to FIG. 1 to the open state according to FIG 2, the spring 6 causes the stationary-side cavity block to move 20a relative to the block 4. The stationary-side cavity block 20a therefore becomes relative moved to the hot runner block body 10 so that the contact surfaces 25a the openings the gates 13 close and thereby the leakage of the molten resin from prevent the gates.

At the same time, the sprayed objects 40 are still separated from it Resin in the liquid state separated.

On the other hand, through the opening of the mold, the movable die platen becomes 3 withdrawn until it rests against a base plate (not shown) of the injection molding machine bumps. On this occasion, the ejector rod 9 strikes against a (not shown) Projection on the base plate and is in relation to the fixed block 5 according to Fig. 2 moved to the right. The ejector pins 9b connected to the ejector rod 9 connected plate 9a are carried, the molded articles 40 push out of the Mold cavities 21 from.

In the form described above with a heated inlet is the Construction of the gates greatly simplified and the distance between adjacent ones Gates, i.e. the basic dimension in which the gates are arranged, is minimized because the independent installations of heat control devices and valves for prevention the leakage of resin for the respective gates are omitted. Because the gate openings closed by the contact surfaces of the cavities in the manner described above become, various troubles such as molten resin leakage become from the gate openings, largely switched off.

However, this construction has a serious disadvantage because namely in this form the heated inlet block, which is at a high temperature must be kept in contact with the over the entire period of the casting process There are cavity blocks that are kept at a low temperature. The temperature the gates, which are arranged near the boundary between the hot and cold parts therefore tends to be at times when the door temperature is sufficiently high must be, i.e. in the injection times, to drop below this required value. On the other hand, the cavity block, which must be cold enough to solidify of the resin to allow easy to warm.

It is proposed to maintain a sufficiently high temperature of the doors been to further bake out the entire hot inlet block or a device to be provided specifically for heating the areas around the goals.

However, the first solution has proven useless because it is light excessive heating of the resin passages takes place what may even lead to thermal decomposition of the resin.

The second solution is also disadvantageous because the heat flow increases the cavity blocks is reinforced so that a sufficient cooling of the objects is prevented.

This may lead to various difficulties like that Loss of dimensional accuracy as well as bulges and deformations on the objects.

The object of the invention is to create an improved injection mold, which is suitable for simultaneously molding a number of objects, and with which avoids the disadvantages of the known injection molds explained above, with the relevant advantages such as prevention of resin leakage, however to be kept.

To solve this problem, the invention provides that a Gate temperature recovery block is provided against the one surrounding the gates Areas can be created in at least part of the period in which the gates and the inlet openings do not lie against one another.

Basically, the temperature required for the casting process is around the Gates of the hot runner block around is needed after a brief lowering restored by surface contact. This idea is made in a negative way by it carried out that that part of the hot runner block that surrounds the gate, at the latest immediately before the injection is separated so that the area surrounding the gates of the hot runner block cools less easily than it would if it were in Contact with the cavity blocks would be held.

At the same time, this idea can be put into practice by that a hot block specially placed near the gates is in contact with that part of the hot runner block that surrounds the gates. if the process to the injection step is advanced, the area around the Gates around held so that an easier cooling is possible, so that the temperature the gates cannot get excessively high.

More particularly, the present invention relates to a new construction a hot runner mold, which is advantageous for the simultaneous molding of a number can be used by objects without the molten resin leaking or the gate clogged with molten resin.

The mold works flawlessly and represents a good quality of the manufactured Objects safe by appropriate cooling and hardening of the resin.

First, to construct the mold of the present invention is a heating inlet block necessary. This has a device that keeps it at a certain high temperature holds. An inlet port is also provided through which the molten resin is driven into the hot runner block. The melted product passes through outlets Resin from the hot runner block into the mold cavities, through the gates, which are narrow passages, and through a pouring opening on each Mold cavity.

There must also be a cavity block. This will be on a kept certain low temperature, and he has cavities in which the molten resin is poured and in which it cools and hardens, so that the objects arise. Pouring openings lead into the cavities, into which the resin is injected from the gates.

Finally, there is a block that shows the door temperature according to the Restores cooling. This door temperature recovery block has the function of that it maintains the high temperature of the gate upon contact of the gate area with the hot runner block restores. In other words: the door temperature recovery block heats the gate area, which as a result of direct contact with the cavity block on a lower temperature had been brought back up to a higher temperature.

This fourth requirement has the following function.

The gates of the hot runner block and the pouring holes of the cavity block for the molten resin are at least at the time of injection into mutual Aligned so that those areas of the hot runner block that the Surround gates, come in contact with the cavity block. The hot runner block and however, the cavity blocks are designed to move relative to one another so that the gates of the hot runner block and the pouring openings for the molten resin on the cavity block are separated from each other so that the touch contact the gate area and the cavity block is interrupted. At the same time is the construction so that the aforementioned gate temperature recovery block has at least one Part of the time that the gates of the hot runner block are removed from the pouring spouts of the cavity block are removed, in contact with the door area brings will.

The injection mold according to the invention has the above-mentioned constructive features Characteristics.

The term "means for maintaining the hot runner block on a certain high temperature "does not mean a facility that covers the entire part of the hot runner block over the entire period of the injection molding process on one maintains a constant temperature. Such a facility would actually be outside are within the scope of the invention. In detail, the temperature of the door area lowered to such a low level at the time of the completion of the injection, that the free flow of the resin is interrupted. This point actually forms a critical feature of the device according to the invention.

The term means that the hot runner block is on a particular Temperature holds "therefore generally refers to a device that maintains the temperature of the Hot inlet blocks in combination with the heating by the gate temperature recovery block brought to such a level as is necessary for free flow of the molten resin is required. However, this only applies to the period after which the goal area is in Contact with the gate temperature recovery block has been made by the time the start of the next injection batch.

The injection mold according to the invention with the design features described above can be practically implemented in various forms, which is in detail from the Shapes of the items to be manufactured and the type of injection molding machine used as well as other conditions.

Some exemplary embodiments are described below with reference to the figures the invention explained in more detail.

Fig. 1 shows schematically a longitudinal section through a conventional one Injection mold with hot inlet in the closed state, i.e. in the injection state, Fig. 2 shows a view similar to that of FIG. 1 with the mold open, FIG. 3 shows a schematic representation of a mold with heated inlet according to a first Embodiment of the invention in the closed state, partially in section, Fig. 4 shows schematically a longitudinal section through another embodiment of the invention in the closed state, Fig. 5 shows a longitudinal section through the shape of Fig. 4 in Closed state, but not ready for injection, FIG. 6 schematically shows a Longitudinal section of a further embodiment of the invention in the closed state, Fig. 7 shows a section similar to that of FIG. 6, but with the shape in the open state FIG. 8 shows a schematic representation of a further embodiment of FIG Invention in the closed state, Fig. 9 shows schematically a longitudinal section through a further embodiment of the invention in the open state, Fig. 10 shows a representation of the mold according to FIG. 9 in the closed state, FIG. 11 shows schematically a longitudinal section of a further embodiment of the invention in the open state, FIG. 12 shows the mold according to FIG. 11 in the closed state, and FIG. 13 shows one schematic longitudinal section of a further embodiment of the invention in a Position not intended for injection.

Fig. 3 shows a very simple embodiment that by changing the known shape shown in Figs. 1 and 2 has arisen. The injection mold the first embodiment of FIG. 3 differs from the known Injection mold essentially in that it is equipped with a regeneration block for the Gate temperature is equipped.

In detail, the mold block with a hot mold inlet consists of a heated inlet liner 10a and a block body 10 with a hot inlet. The hot one Inlet sleeve 10a is via a mounting block 4 with a stationary side Tool plate 2 connected to an injection molding machine and attached to it. The movement side Cavity block 20 is on a moving-side mold plate of the injection molding machine attached with suitable fasteners while between the moving side Cavity block 20 and the fastening block 4, a stationary-side cavity block 20a is arranged. One between the stationary side cavity block 20a and the Mounting block 4 arranged Opening device 6 pushes this both parts elastically apart. The route over which the two parts meet Can move apart is limited by a stop 7.

In one end of the hot inlet sleeve 10a of the hot inlet block opens a molten resin supply port 11. The melted resin, i.e. the Molding material that has been injected from the nozzle of the injection molding machine, thus flows through the opening 11.

The molten resin continues to flow through the inlet channel 12a, which starts from the opening 11 and runs in the same direction in which the movable Part is moved when opening and closing the mold.

The block body 10 with hot mold gate forms a structure which is substantially perpendicular to the above-mentioned direction in which the movable mold part is moved, and has two parallel opposite one another Gate opening surfaces 15. A plurality of gates 13 open along each gate opening area 15 the length of the block body 10. These gates are available via corresponding auxiliary channels 12c with a main channel 12b in connection, which runs in the longitudinal direction of the block body 10 runs. The main channel 12b crosses the main inlet 12a. In part of the block body 10, a heater 14 is embedded which heats the body 10 so that the Resin can flow in it at least at the time of injection.

Of course, in the inlet sleeve 10a as well, if necessary Heating devices may be provided.

The movement-side cavity block 20 has two opposing set Contact surfaces 25 on the respective door opening surfaces 15 of the block body 10 can rest at least in the closed state of the mold. The cavities 21 border to the dividing surface 23 of the cavity block 20. These cavities each have Inlet openings 21a for molten resin, which are in the contact surfaces in at the points of the contact surfaces corresponding to the points of the gates 13 to open.

The stationary-side cavity block 20a has two opposite one another Contact surfaces 25a on the respective door opening surfaces 15 of the block body can concern.

The regeneration blocks 30 for the door temperature are in suitable areas of the stationary-side cavity block 20a attached so that their contact surfaces 35 lie in the same planes as the corresponding contact surfaces 25a of the stationary-side cavity blocks 20a.

In this way the door opening surfaces 15 are the contact surfaces 25 of the cavity block 20 on the moving side, the contact surfaces 25a of the stationary side Cavity blocks 20a and the contact surfaces 35 of the regeneration blocks for the gate temperature arranged so that they run in the same direction as the movable one Part of the shape is moved.

The stationary-side and the moving-side cavity blocks 20a, 20 are each equipped with lines or passages 24a, 24 for cooling water, around these void blocks at a sufficiently low temperature for solidification of the resin.

In the open state of the mold, which is shown in Fig. 3, the stationary cavity block 20a held at a distance from the mounting block 4, wherein the distance is limited by the stop 7. In this state, the door opening areas 15 of the block body held in a position in which they on the regeneration blocks 30 is applied for the gate temperature. Therefore, a uniform pattern is created around the gates Temperature distribution as a result of the heat input from the regeneration blocks 30, or even if such a heat input cannot be expected, it takes place through the Presence of the regeneration blocks 30 from a suppression of heat radiation the goal area, while a continuous supply of heat from other parts of the Block body takes place in the goal area.

In this way, a temperature is established in the area around the gates 13 creates or sustains that is high enough to cause injection or flow of the resin. The moving-side mold plate of the injection molding machine is moved in this state in the closing direction of the mold. In detail will be first the dividing surface 23 of the moving side cavity block 20 in contact with the Brought dividing surface 23a of the stationary-side cavity block 20a. Then press a mold clamping device toward the stationary-side cavity block 20a on the mounting block 4 until the block 20a comes into contact with the block 4, the biasing force of the mold opening device 6 overcomes and thereby the mold eventually closes completely. During this closing process the form will be moves the gate opening surfaces 15 relative to the gate temperature maintenance blocks 30, as a result of the movement of the stationary-side cavity block 20a. At the same time the gates 30 are moved relative to the cavity blocks so that the gate openings 15th the temperature maintenance blocks 30 release and in contact with the contact surfaces 25, 25a of the cavity blocks come. After all, the Gates 13 in alignment with the corresponding molten inlet openings 21a Resin brought.

The injection of the molten resin starts immediately after completion the closing process of the mold. The moment the form closes is ended, namely the door opening surfaces 15 are already in contact with the cold Cavity blocks and the temperature of the gate area is already starting to drop and cause the resin to solidify in the area concerned. It is therefore required to start the injection before any serious solidification begins. As tests in normal injection molding processes have shown, the continuous Maintain flow of resin once started, even at temperature is lowered significantly around the goal area.

When the mold cavities 21 are filled with the resin, the resin The flow ends and the resin begins to solidify.

At the moment the hardening begins, no further flux is melted Resin and therefore no longer required injection pressure. This means that the Injection step is over. Then the next step of cooling begins, in which the molten resin filling the mold cavities 21 from the injection pressure released and adequately cooled. Prepare during this cooling step the injection molding machine prepares itself for the next resin filling through a process the as Plasticization is called.

The opening of the mold begins when the cooling step is completed. This The opening process begins with a simultaneous and uniform movement of the two Cavity blocks 20, 20a created by the mold opening device 6. The hardened resin is then in the areas between the gates 13 and the inlet openings 21a separated or trimmed so that the injection molded parts from the so-called inlets are exempt. The stop 7 stops the movement of the stationary-side cavity block 20a after the door opening surfaces 15 have been brought into the previously mentioned positions have been in which they are on the corresponding contact surfaces 35 of the temperature maintenance blocks 30 are present. Then the dividing surfaces 23 and 23a are moved apart, and the molded articles are ejected. After ejecting the molded articles the moving side cavity block 20 is stopped and one cycle of the molding process is finished.

In the injection molding process described above, it is critical that the Hardening of the resin begins at an early stage of the injection, leaving the free Flow of the injected resin can be hindered. As a result of a test, carried out by the inventors is dimensional or weight stability or uniformity of the manufactured objects significantly improved if one allows curing to begin early in the injection process, in comparison in the event that the molten resin is already withdrawn from the injection pressure, if it still has great pourability.

The hardening process begins in the case of the one according to the invention system at an early stage of the injection, which is the case with the conventional mold design 1 and 2 is not possible at all. Such an early start to hardening is not possible with the conventional molding system because there is no facility here is provided for melting hardened resin in the gate area, so that the gates clogged would if the resin were already partially hardened in the gate area. Therefore In the known machines, the next injection process would be carried out by the hardened resin parts are obstructed.

The practical form of the exemplary embodiment will now be described in more detail explained.

The gate temperature maintenance block 30 is an essential feature the invention. It is used to keep the temperature of the door area high enough Maintain or recover contact with it when the temperature is up of the goal area as a result of the previous contact of this area with the cold Cavity blocks has sunk. The gate temperature block 30 therefore consists of heat insulating Material that transfers heat less well than the material of the cavity blocks, e.g. made of asbestos, ceramic, heat-resistant plastic or porous material, or alternatively, it is designed so that its temperature is higher than that the cavity blocks.

It has been found that the former way in which the gate temperature recovery block 30 contains or consists of a heat insulating material is practical and leads to sufficient results.

Preferably, however, the door temperature recovery block is made from a composite material in shape one thin (approx 1 pm to 1 mm thick) film of a metal on the sliding surface of the heat-insulating Materials to better tolerate the improved service life and the to create higher temperature recovery of the door area. Although not here described in detail are various embodiments of the door temperature recovery block made of composite materials (composite materials), including various Thermal insulation materials are possible.

The latter way in which the gate temperature recovery block is kept at a temperature greater than that of the cavity block, is cheaper. The desired beneficial effect arises from the fact that the gate temperature recovery block 30 contains its own heating device, so that the temperature of the block 30 is at least is kept higher than the temperature of the cavity blocks. It is clear that the Effect of temperature recovery is greatly improved by increasing the temperature of the gate temperature recovery block 30 is kept substantially the same or higher is used as the predetermined temperature to which the hot gate block is heated. A stable and even casting process of the objects is also ensured by that means is provided that a constant high temperature of the gate temperature recovery block 30 maintains.

For this purpose, for example, an electric heater, the circulation a hot heating medium or heat pipes may be provided around the gate temperature recovery block 30 to heat. These measures offer the advantage of simple temperature control to maintain the constant high temperature of the gate temperature recovery block.

The ability to recover or maintain the high The temperature of the door area is increased by changing the temperature of the door temperature recovery block makes itself sufficiently high. Too high a temperature caused this block however, various troubles such as disintegration of the resin and the like.

To achieve the temperature recovery effect without doing a causing excessive heating of the gate temperature recovery block proposed the block made of a material with good thermal conductivity and great Heat capacity, large specific heat and specific weight.

From this point of view, it is preferable as the material of the gate temperature recovery block Related to copper or its alloys, although other metals are generally applicable are.

Also to have good temperature recovery around the gates of the hot runner block To ensure that a device is preferably used, which is the gate area of the hot runner block pushes against the gate temperature recovery block when both have been brought into mutual contact.

According to FIG. 3, two door temperature recovery blocks 30 are attached to one another opposite sides of the stationary-side cavity block 20a mounted. Of the State of mutual contact of the door opening surfaces 15 and the appropriate Areas 35 of the blocks 30 depends on the state of attachment of the blocks 30 and of the block 20a, which in turn depends on the relationship between the distance of a touch surface 35 depends on the other and the distance of a door opening surface 15 from the other.

The optimal state of attachment is theoretically achievable, however the practical execution often fails due to the thermal expansion of the individual parts and / or at the practical accuracy limits of the mechanical Editing. The attachment can be made excessively tight, allowing the smooth movement of the two parts is obstructed, or it can also be too loose on the other hand, so that there is insufficient contact between the two parts.

This problem is avoided in a favorable manner that at least one of the door temperature recovery blocks 30 perpendicular to the interface 35 is made movable by a certain amount, and a clamping device, for example in the form of a spring is provided. This facility becomes whole generally as "device for resilient biasing of the gate temperature block in Contact with the hot inlet block ".

Use of this device is not only in the embodiment 3 possible, but also in the remaining exemplary embodiments described.

The above description has mainly been made in connection with Temperature recovery performance of the door temperature recovery block at the Achieving the desired high temperature in the door area.

In addition to the temperature recovery effect described, the door temperature recovery block an additional role in preventing molten resin from leaking to play. The leakage of molten resin from the gates 13 is prevented by that the gate temperature recovery blocks on the gate opening surfaces of the hot runner block and close them.

Preferably, a heat insulating layer made of air or a other heat insulating material between the temperature recovery block and the part to which the block is attached.

The following is a description of the movement of the hot runner block and the cavity blocks relative to each other.

The entire design of the mold is greatly simplified if one is arranged so that the movement of the hot runner block relative to the cavity block by the operation of the injection molding machine used to open and close the mold, as in the case of the embodiment of FIG. 3. In general terms, the Cavity block group designed to be separated into at least two parts or is divided, namely the movable and stationary part, to the separation to allow the molded objects out of the mold. There is also a case in which the cavity block group is divided into more than three parts to hold objects to be able to manufacture with complicated shapes, or if an adaptation to a corresponding one Ejection system for the items is required. In the event that the cavity block group is divided into two parts, preferably the hot inlet block relative to the moving-side and stationary-side cavity blocks that form the Accompany the opening and closing process of the mold, made movable by the hot runner block via a mounting block on a pair of die plates of the injection molding machine is attached, and the stationary-side cavity block with the mounting block so connected that it has a free movement of a certain length in the direction of the Perform opening and closing movement of the mold relative to the mounting block can, while the cavity block on the moving side on the other die plate of the Injection molding machine is attached.

The mounting block as used in this facility is only an intermediate connector for attaching the mold to a die plate the injection molding machine, and can therefore also be omitted. That with the one described Embodiment a mounting block # is present is therefore not important.

The hot runner block is preferably moved into and from contact with the gate temperature recovery blocks in connection with which or caused by the movement of the hot runner block with respect to the cavity blocks, which in turn is preferably related to the time of the opening and closing movement the shape takes place. For this purpose, the gate temperature recovery block is at certain Parts of the stationary-side cavity block or a mounting part attached, which can be considered integral with the cavity block. The Gate area of the hot runner block in contact with the gate temperature recovery blocks brought when the mold is opened. At the same time when the mold is closed a relative movement between the hot inlet block and the gate temperature recovery block corresponding to the movement of the stationary-side cavity block with respect to the Hot runner block created so that the gate area of the hot runner block is the gate temperature recovery blocks can leave.

A practical embodiment of the connection between the stationary side Cavity block and the mounting block to achieve the above-mentioned relative movement has a limiter to limit the relative movement of the mounting block with respect to the stationary side cavity block, so that when these parts around the are as far away from each other as possible, permitted by the governor, the gate temperature recovery blocks at the predetermined areas of the hot runner block fit around the gates. A suitable opening device is also provided, which forcefully pushes these two parts apart.

Most of the force applied by the opening device to move the two parts apart is consumed by the fact that those Parts of the resin that have cured between the gates of the inlet block, and the corresponding synthetic resin sprues of the cavity block are sheared off. A part the force is used to overcome the frictional resistance between the sliding parts needed.

The opening device can practically consist of a spring to to make the entire molding system easier to construct. When the opening device but has a great power to exert over a long distance, it preferably consists from a hydraulic or pneumatic tic cylinder.

As has already been stated, it is expedient to use the movements the hot runner block and the cavity block (or the gate temperature recovery blocks) relative to each other by the opening and closing movement of the mold. This is particularly with a view to simplifying the entire molding system cheap and a practical example of such an embodiment has already been will be described with reference to FIG. 3.

In the embodiment of FIG. 3, however, the mutual contact the gate area of the hot runner block and the gate temperature recovery block sustained only for a small part of the period in which the mold opened is maintained so that the recovery of the desired high temperature at the Gate area may not be possible in some cases.

In order to improve this, a device is provided which allows relative movement between a hot runner block and the cavity blocks regardless of the opening and causing the mold to close so that the hot runner block is relative to the cavity blocks is moved such that the gate area of the hot runner block out of contact with the cavity blocks and in contact with the gate temperature recovery block comes before the mold is opened. From a practical point of view it is not It is important that the gates of the hot runner block are in alignment with the entry ports for the molten resin of the cavity block after the injection step is finished. You can therefore perform the above-mentioned relative movement at this stage, i.e. after Completion of the injection step and before opening the form. The above effect is obtained when the relative movement is immediate is initiated before the start of the opening of the mold.

In order to achieve the described operational sequence in the simplest possible way, the hot runner block is preferably connected to one of the two tool blocks the fastening block connected to the injection molding machine fastened in such a way that the hot runner block moves independently of the opening and closing movement of the mold can be.

In the motion block as used in this embodiment is not a specific construction, but just a connecting part for connecting the mold to the tool plate so that the mounting block also omitted or alternatively made in one piece with the stationary-side cavity block can be.

4 and 5 show a preferred embodiment of the hot inlet mold, which is basically constructed according to the principle explained above. A mounting block 4, which is made in one piece with the stationary-side cavity block attached to the stationary-side tool plate 2 of the injection molding machine, while the movement-side cavity block 20 with the movement-side die plate 3 the injection molding machine is connected by suitable intermediate connecting parts.

The nozzle 1 of the injection molding machine is in the directions of the arrows A and B are movable and is located at one end of the hot runner sleeve 10a of the hot runner block at. The hot inlet bushing 10a leads through the mounting block 4 by, by moving in the directions of arrows A and B relative to the mounting block 4 can move within a predetermined range.

Between the mounting block 4 and the hot runner sleeve 10a is a pretensioning device is arranged, which the hot runner sleeve 10a in the direction of the Arrow B, so in contact with the nozzle 1, drives.

The hot runner sleeve 10a is provided with a flange 10b which can be applied against a part of the mounting block 4. The construction is made so that the gates 13 formed in the body 10 of the hot runner block with the molten resin inlet ports 21a in the moving side Cavity block 20 are aligned when the hot runner sleeve 10a with its flange 10b rests against the part of the fastening block 4 mentioned above.

In this embodiment, the nozzle 1 moves in the direction of the arrow A, overcomes the force of the biasing spring 8, so that the inlet bushing 10a with its flange 10b against the fastening block during the injection 4 sets, as Fig. 4 shows. Then, after the injection is finished, the hot runner block moved back by the bias spring 8 following the movement of the nozzle 1, when this is withdrawn in the direction of arrow B, so that the gates 13 are are now no longer in alignment with the inlet openings 21a.

Finally, the hot runner block is moved to such a position that its gate opening surfaces 15 on the contact surfaces 35 of the gate temperature recovery blocks 30th which are attached to suitable parts of the mounting block 4. i.e. into the position shown in FIG. The movement of the hot runner block in the direction of of arrow B is terminated when the hot runner block against the mounting block 4 bumps.

In the illustrated embodiment, the movement of the hot runner block is suspended on the movement of the nozzle of the injection molding machine. However, this construction is neither important nor critical. For example, the contact of the hot runner block sliding or rotating with the nozzle and the means for driving the movement of the hot inlet block can be selected according to the respective type of contact.

Recently it has become common to use the nozzle on injection molding machines to make it displaceable within a certain range, so that the machine Can be combined with different types of shapes and molding methods. Man can therefore move the nozzle in a similar manner to using the mold movement exploit.

It is therefore possible to significantly simplify the overall structure, using the movement of the nozzle of the injection molding machine as the source of the driving force for causing the relative movement between the hot runner block and the mounting block is exploited (this mounting block can be the same body like one of the cavity blocks). From the standpoint of simplifying the mold construction the hot runner block is preferably attached to the nozzle of the injection molding machine, while the nozzle can be moved within a certain range of motion. However, this arrangement brings the problem with it being that it's pretty it is difficult to connect the hot runner block to the nozzle by attaching the mold the injection molding machine is attached.

Apparatus is preferred to overcome this difficulty provided, which presses the hot runner block elastically against the nozzle. This device is located between the hot runner block and the mounting block or a equivalent part of the shape. In the simplest case, it can consist of a spring. However, if a force is required over a longer distance, a hydraulic Cylinder or a pneumatic cylinder can be used.

In order to eliminate unnecessary parts of the mold, the Moving the gate area of the hot runner block towards the gate temperature recovery blocks and in the opposite direction by the relative movement between the hot runner block and the cavity blocks, even if the relative movement is independent of the opening and closing movement of the mold is performed.

For this purpose the door temperature recovery blocks are attached to the Fastening block or attached to an equivalent molding, so that the gate area of the hot runner block corresponding to the movement of the hot runner block relative to the cavity blocks in and out of contact with the gate temperature recovery block can be brought.

The following is a description of the shapes of the hot runner block itself and the shapes of mutual contact between hot runner block and cavity blocks.

In the embodiment of FIG. 3, the contact is the hot runner blocks and the cavity blocks so that the door opening surfaces and the surfaces in which open the inlets for the molten resin, at least at the time of injection may come into contact. At the same time, these surfaces extend in the direction the relative movement between the hot runner block and the cavity blocks. These The form of contact offers the advantage that the hardened resin can be separated the parts between the gates and the inlets for the molten resin as a result of the movement of the hot runner block relative to the cavity blocks a certain period of time following the completion of the injection Shearing takes place so that the separation is carried out uniformly for all objects and all objects are manufactured with the same dimensional accuracy and uniformity will.

Even if the door opening areas as well as the areas in which open the inlet openings for the molten resin, in the direction of the relative movement run between the hot runner block and the cavity blocks does not mean that always that these surfaces are flat, as shown in Fig. 3, but they can also be cylindrical, as in the embodiment of FIG. 8.

According to FIG. 8, the hot runner block has a block body 10 cylindrical shape, the axis of which is in the direction of the opening and closing movement of the Shape runs. Several gates open in the peripheral surface of the cylindrical hot runner block, which forms the door opening area 15. The gate temperature recovery block 30, the is attached to the stationary side cavity block 20a, has one cylindrical contact surface 35 which bear against the cylindrical door opening surface 15 can. The movement-side cavity block 20 has a cylindrical contact surface 25, which abut the cylindrical gate opening surface of the hot runner block can and into which the inlet openings 21a for the molten resin open, so that they come into alignment with the gates at the time of injection.

At the time of injection, the gate opening surface 15 is in contact with the area 25 in which the inlet openings for the molten resin are located, and the hot runner block is moved relative to the cavity blocks in the direction of the opening and closing movement of the mold moves so that the gates 13 and the inlet openings for the molten resin to be shifted against each other, leaving the hardened resin is sheared between them. Eventually, the gate opening surface 15 comes into contact brought to the contact surface of the gate temperature recovery block 30.

The described arrangement of the gate opening area and the inlet opening area meets the requirement that these surfaces are in the direction of relative movement the hot runner block and the cavity blocks must move towards each other. Additionally this arrangement has the advantage of simpler machining of the hot runner block, because this is cylindrical and also offers the further advantage that a larger number of gates can be attached to the limited gate opening area can, so that a large number of objects can be molded at the same time is.

Advantages of a completely different kind arise when the consortium construction is such that the gate opening surface of the hot runner block and the mating surface of the cavity block are touching each other at the time of injection, but these surfaces at an angle to the direction of relative movement between the hot runner block and the cavity blocks which may be a right angle.

Namely, in such a case, the above-mentioned inlet openings for the molten resin substantially or completely omitted so that the molded articles hardly have an unnecessary gate or no gate at all have, as can be seen in more detail from the following description.

It is assumed that the material or the body of the resin gates is omitted compared to the previous embodiments in which the Gate opening area and the interacting contact areas in the direction the relative movement between the hot runner block and the cavity blocks. In this case, the gate openings themselves form part of the respective mold cavity.

In such a case, the surfaces of the molded articles scratched from the gate opening surface when the hot runner block is relative to the Cavity block moved.

However, if these faces are at an angle to the direction of the above mentioned relative movement to each other, which can be a right angle, then scratching of the surfaces of the molded articles occurs through the door opening surface less easily.

Figs. 6 and 7 show an example of a mold construction, at the gate opening area and the contact area from which the inlet openings for the molten resin exit at right angles, under one of a right angle deviating angle to the direction of the above-mentioned relative movement are.

6 and 7, the hot runner block has a body 10, the Long sides run in a direction perpendicular to the plane of the drawing. The long sides of the body 10 thus run at right angles to the direction of the opening and closing movement the form. The body 10 of the hot runner block has two gate opening surfaces 15, which run in the longitudinal direction of the body 10 and to the direction of the opening and Closing movement of the mold are oriented at an angle. At the same time, the body is 10 also equipped with parallel, opposite contact surfaces 16, that in the longitudinal direction of the body 10 parallel to the line of the opening and closing movement run out of shape. In each gate opening area 15 there are several gates 13, which are arranged one behind the other in the longitudinal direction of the body 10 and are open. The gates 13 are narrow open channels.

The cavity block 20 on the movement side is provided with contact surfaces 25, in which a plurality of openings 21a for the passage of molten resin are thus arranged are that they are at the time of injection (see Fig. 5) with the appropriate gates 13 are aligned. The openings 21a lead to the mold cavities 20. The stationary side Cavity block 20a supports the door temperature recovery blocks 30 so that the contact surfaces 16 of the body 10 of the hot runner block in contact with the respective gate temperature recovery bodies 30 are brought, when the mold is opened or in a predetermined State as shown in FIG. 7.

The hot inlet mold described has the features of the invention on. In addition, as can be seen from the drawings, is the body of the openings omitted for the molten resin. The openings for the molten resin are therefore materially part of each mold cavity in this embodiment, of which the gate in question is a wall.

In the embodiment described, in which the door opening surfaces and the contact surfaces interacting therewith obliquely to the direction of the relative movement run between the hot runner block and the cavity block, these surfaces can be flat, as shown, or alternatively conical.

An arrangement of the inlets similar to that of the exemplary embodiment can also be used of Fig. 3 where these surfaces are flat. In such a case a main gate extends in the longitudinal direction of the body of the hot gate block. The gate opening surfaces are arranged back to back parallel to the main gate. Several gates open into each of the flat gate opening surfaces.

In this way you can have a larger number of molded parts at the same time than with an inlet block that has only a single door opening area. Additionally there is the balance or stability of the hot runner block itself much improved.

On the other hand, you get benefits similar to those that go through the cylindrical door opening surface is created, i.e. a light one Machining of the hot runner block, even if the door opening surface is conical power. At the same time, the number of items to be produced at the same time is increased expediently increased when the door opening surface becomes conical, which is the case the cylindrical door opening surface happens.

9 and 10 show an embodiment in which the door opening surfaces and the interacting contact surfaces into which the passage openings are located open for the molten resin, perpendicular to the line of relative movement mentioned above get lost. In detail, the hot runner block according to FIGS. 9 and 10 has a body 10, the long sides of which are perpendicular to the plane of the drawing and a substantially uniform cross-section over the entire length of the body 10 have, with the exception of an inlet channel 12a, branch channels 12c and gates 13. The body of the hot runner block is a part whose longitudinal axis is perpendicular to the Drawing plane runs and which has a main channel 12b, which extends in the longitudinal direction runs. The body 10 also has two substantially flat contact surfaces 16, which run parallel to the main channel 12b and to the direction of the opening and Closing movement of the mold are inclined. These two contact surfaces 16 converge at a point below the body of the hot runner block. Each contact area 16 is partially covered with a heat-insulating recess 17. The lower end of the body 10 forms a substantially flat door opening surface 15 which is at right angles runs in the direction of the opening and closing movement of the mold. In the body 10 of the hot runner block there are several gates 13 which are arranged in a row are and open into the door opening area 15. These Gates 13 are connected to the main channel 12b via the respective branch channels 12c.

The stationary side cavity block 20a is shaped so that it the Enclosing body 10 of the hot runner block from both sides. He owns two Contact surfaces 25 against which the two contact surfaces 16 of the hot runner block can be placed at least at the time of injection. In predetermined places of the cavity block 20a, two gate temperature recovery blocks 30 are arranged.

Each of these door temperature recovery blocks 30 has a contact surface 35 placed against the corresponding contact surface 16 of the hot runner block can be, as well as a heater 34. For pretensioning the respective gate temperature recovery blocks A pretensioning device 31 is provided against the contact surfaces 16.

The door temperature recovery blocks 30 are slidable on the stationary side Cavity block attached so that they can be moved in the direction in which the pretensioning force of the pretensioning device 31 has.

The moving side cavity block 20 has a plurality of mold cavities 21, the openings for the individual gates of the hot runner block possess molten resin. The cavity block 20 also has a surface 25, into which the above-mentioned inlet openings 21a open. The surface 25 can be in contact with the gate opening surface at least at the time of injection to be brought. In the exemplary embodiment described, this area becomes 25 formed by the same surface as the dividing surface 23. In this way forms the surface 25 a part of the dividing surface 23, which the neighboring Mold cavities separates from each other.

When using the form are during the injection when taking the form 9 is kept closed, the mold cavities 21 from both the cavity blocks and closed by the gate opening surface 15 of the hot runner block. To the same Time the contact surfaces 16 of the hot runner block in contact with the contact surfaces 25a of the stationary-side cavity block 20a held while the gate temperature recovery blocks 30 rest against the heat-insulating recesses of the corresponding contact surfaces 16. In this way, the door temperature recovery blocks 30 are out of contact with brought to the hot runner block.

If then the mold is opened or after a predetermined one Time has passed after the injection is completed, the hot runner block becomes relative to both hollow space blocks in the direction of the opening and closing movement of the mold moved so that the gate temperature recovery blocks 30 in contact with the in immediate Areas of the contact surface 16 located near the gates 13 come.

In this embodiment, the door opening area extends and the area into which the openings for the molten resin open, perpendicular to the direction of relative movement between the hot runner block and the cavity blocks. The inlets for the molten resin on each Casting molds are not required and have therefore been omitted.

In the previous exemplary embodiments of FIGS. 3, 6 and 7, as well as 9 and 10 the door opening surface touches the appropriate Area into which the inlet openings for the molten resin extend, at least at the time of injection and these areas are all essentially just. This feature offers the advantage that there is little difference in thermal Expansion between the contact surfaces is allowed, thanks to the flat shape of these Surfaces, and that such different thermal expansions are not impermissible cause high and uneven internal stresses in the mold.

Therefore, there is always good surface contact between the contact surfaces maintain.

In the embodiments of FIGS. 6, 7 and 9, 10, the gate temperature recovery bodies made so that they touch the hot runner block near the gates in places where which, however, are not the door opening areas.

This arrangement is quite effective and useful when used in combination used with some special shapes of hot runner block.

However, this arrangement may present the problem of leakage, i.e., leakage of molten resin from the gates because the gates are from the gate temperature recovery blocks not be kept tightly closed.

However, this problem can be solved by making the resin material normally solidified in the gate area when the gates are opened and only melts again immediately before the start of the next injection batch. This critical condition is set by changing the thermal insulation or the heat capacity of the door temperature recovery blocks appropriately or alternatively by suitable choice of the period of time over which the gate area of the hot runner block in contact kept with the gate temperature recovery blocks will.

The following is the most developed embodiment of the Invention explained in more detail with reference to FIGS. 11 and 12. The body 10 of the hot runner block is in this embodiment a block that is two-dimensional in the direction perpendicular to the direction of opening and closing movement of the Shape extends.

The body 10 has a number of cylindrical or columnar shapes rod-like parts 18 on which from him in the direction of the opening and closing movement stick out from the shape. Each rod-like part 18 does not have its own heating device. The lower end of each rod-shaped part 18 forms the door opening surface 15, into which a single gate 13 opens in the form of a narrow channel.

The peripheral surface just above the door opening surface is conical in shape and forms a conical contact surface 19, which is arranged with the cylindrical above Surface 16 is connected. The between the cylindrical contact surface 16 and the Body 10 lying area of the rod-shaped part has a diameter that is smaller than that of the cylindrical contact surface 16. Each port 13 is over a branch channel 12c connected to the main channel 12b, the longitudinal direction and runs across the body 10 of the hot runner block. The main channel 12b protrudes a lug 12a in connection with the nozzle of the injection molding machine.

The stationary-side cavity block 20a has bores which respective rod-shaped parts 18 are surrounded.

The bottom of each hole forms a conical cone tact area 25a, which are in contact with the contact surface 19 of each rod-shaped part 18, at least at the time of injection.

The body 10 of the hot runner block is itself on the mounting block 4 attached.

The stationary-side cavity block 20a is with the mounting block 4 connected in such a way that it has a predetermined through the opening process of the mold Distance from this and brought closer to him during the closing process of the mold will.

The moving side cavity block 20 has a plurality of mold cavities 21 to form inlet ports 21a for the molten resin. The inlet openings 21a each correspond to the gates 13. Furthermore, the block 20 has a dividing surface 23 provided against the dividing surface 23a of the stationary-side cavity block 20a is placed when the mold is held closed.

A carrier body 30a runs two-dimensionally parallel to the body 10 of the inlet block. The carrier body 30a contains a heating device and is attached to the stationary side cavity block 20a via a heat insulating member 33 attached. The carrier body 30a carries a plurality of contact parts 30b, the rod-shaped Parts 18 of the body 10 correspond. Each contact part 30b is tubular and its Inner wall forms a contact surface 35 which is shaped and dimensioned so that brought them into close contact with the contact surface 16 of the rod-shaped part 18 can be. The carrier body 30a, the contact parts 30b and the heat insulating Materials 33 form in combination nation has a door temperature recovery block.

In operation, the mounting block 4 and the stationary side Cavity block 20a held in contact with each other, and the block 20a and the moving side Cavity blocks 20 are also held in contact with each other, as shown in Fig. 11, when the mold is in the closed state. In this state, the contact part 30b is like that arranged to have the central reduced diameter portion of each rod-shaped Part 18 surrounds so that this does not interfere with the gate temperature recovery block in Contact comes while the contact surface 19, which is the gate of each rod-shaped Part 18 surrounds, in contact with the corresponding contact surface 25a of the stationary side Cavity blocks 20a is held.

Opening the mold begins with the separation of the mounting block 4 from the stationary-side cavity block 20a.

The contact surface 19 of each rod-shaped part 18 is therefore released from the contact surface 25a of the stationary-side cavity block, and the contact surface 16 of each rod-shaped part 18 is in contact with the contact surface 25 of the corresponding contact part 30b brought.

Finally, the mold is opened to the state that shown in FIG is shown to take.

One of the distinguishing features of this construction is in the fact that several rod-shaped parts, which in the direction of the above mentioned Relative movement between the cavity block and the hot runner block run a Form part of the hot runner block, and that of the gates each at the front of the rod-shaped part is arranged. This increases the freedom in the arrangement tion the cavities are considerably enlarged. At the same time, the heat supply to the mold cavities minimized in favorable form, because the contact of the cavity block and the hot runner block takes place with each other through the end regions of the rod-shaped parts, their thermal Inertia is sufficiently small to ensure good shaping, i.e. a good cooling and curing of the resin. The recovery of the high temperature of the Gate area when it comes into contact with the gate temperature recovery block, takes place in one shorter time than cooling.

This characteristic feature of the superior heat balance becomes evidenced by the fact that the form works satisfactorily without being particular Facilities would be required by which the gate area on a constant high temperature is maintained.

The second characteristic is that each is rod-shaped Part 18 has a central area of reduced diameter, i.e. the face or the front end of the rod-shaped part to which the gate is attached is, has a larger diameter than the remaining areas of the rod-shaped Part so that the gate temperature recovery block can be arranged that it is the intermediate piece of reduced diameter of the rod-shaped part at least at the time of injection is opposite while he is with the gate area of the rod-shaped Part only comes into contact after this the inlet port of the cavity block for melted resin has left. This arrangement therefore shows an effective one and practical construction that allows quick recovery of the high temperature of the gate area of the bar-shaped part made possible by the previous Contact with the cold cavity block has been cooled.

The following is a description of the possible shapes of the rod-shaped Part of the hot runner block and the gate temperature recovery block as well as the Forming the mutual contact of the rod-shaped part and the gate temperature recovery block.

Referring again to the above second characteristic Feature of this embodiment gives better contact between the rod-shaped Part and the gate temperature recovery block by placing the rod-shaped part of the hot runner block provided with an inverted conical peripheral surface, the Diameter towards the lower end of the rod-shaped part on which the gate is arranged is increasing. The contact area of the gate temperature recovery block receives a corresponding inverted conical inner contact surface.

This type of mutual contact can only be obtained through a highly precise Position control of the hot runner block with respect to the gate temperature recovery block, otherwise the mutual contact may or may not be sufficient on the contrary be too strong, so that one of the two parts pressed against each other breaks. It is noteworthy that the precision requirements are lower, and that breakage of the parts is prevented by having a resilient contact between the rod-shaped part and the gate temperature recovery block.

This resilient contact is obtained by providing that the gate temperature recovery block consists of a carrier body and contact parts carried by the carrier body and which by means of a suitable Jig, for example by springs, in the direction of relative movement of the hot runner block to the gate temperature recovery block are freely movable so that the contact parts resiliently against the corresponding rod-shaped Parts can be pressed.

A practical embodiment of this example is shown in FIG.

A support part 30a, which contains a heater 34, is stepped with Provided bores, each of which receive a corresponding contact piece 30b can. The contact piece has a generally cylindrical shape and is flanged provided, which is placed against the step of the hole. A jig in The form of a leaf spring or plate spring 31 is arranged behind the contact piece 30b, which in turn is held in place by a holding piece 30c. The contact piece 30b is held with respect to the support piece 30a so that it is a certain amount can be moved resiliently.

A rod-shaped part 18 which is attached to the hot runner block is, is movably arranged in the bore of the contact piece 30b. The rod-shaped one Part has an inverted conical circumferential surface, the diameter of which goes downwards gets bigger. At the lower end is the gate 13. This inverted conical The circumferential surface forms the contact surface 16 of the rod-shaped part 18. The bore of the contact part 30b has an inner surface, a part of which is inversely conical Has shape that of the inverted conical contact surface 16 of the rod-shaped part is adapted. This inverted conical inner surface of the contact piece 30b forms its contact surface 35. The Diameter of the hole in the contact piece 30b is of course large enough to clear the other part than the contact area 16 of the rod-shaped part to surround.

With this construction there is a slight shift in position of the rod-shaped part 18 in which it comes into contact with the contact piece 30b, absorbed, and achieved as a result of the resilient contact that the above enumerated Benefits can be achieved.

A stable mutual contact of the rod-shaped body with the temperature recovery block is also similar to that shown in Figs Shape of the rod-shaped part 18 can be achieved. In detail the mutual takes place Contact of the rod-shaped part and the gate temperature recovery block through radial contact between the inner cylindrical surface of a bore and a cylindrical outer surface of a cylindrical body. With this construction but no stable mutual contact is guaranteed. This arrangement can however, modified so that a stable mutual contact by resilient Attacking these two surfaces together is achieved.

For this purpose, the area of the gate temperature recovery block is available, that is to come into contact with the rod-shaped part, radially inwards, i.e. it has a reduced inner diameter. The one protruding radially inward Part is provided with suitable slots that are in the axial direction of the rod-shaped Part of the show. In operation, the rod-shaped part is vigorously in contact with the radially inwardly projecting portion of the gate temperature recovery block in this way pressed so that the slots spread apart and thereby the wish solid mutual contact is achieved.

In the embodiment of FIGS. 11 and 12, the st; lncjc ~ rlL # ürnli <Icn Parts of the tie-in block correctly taken up by appropriate contact pieces and contacted with them, which are attached to the support part of the gate temperature recovery block are attached. For this purpose, the contact pieces must be made with high precision the support part are arranged so that they are exactly with the corresponding rod-shaped Parts are aligned. Such a job of arranging and fixing the contact pieces with high precision is extremely difficult to perform. Besides, the precision can easily be lost due to possible thermal expansion of the neighboring parts.

However, this difficulty can be overcome in that the Contact pieces are mounted on the carrier part and movable relative to this. The direction of the desired relative movement is usually perpendicular the direction of relative movement between the gate temperature recovery block and the hot runner block. In this way the gate temperature recovery block exists preferably from a support part and contact pieces, which are rod-shaped with corresponding Parts of the hot runner block can come into surface contact. The contact pieces are on the carrier part and relative to this in the direction at right angles to the relative movement freely movable between the gate temperature recovery block and the hot runner block.

From the above description it can be seen that the invention in Realized in the form of various designs can be of those each with its own particular advantages. The advantages of the invention can be can be summarized as follows: Applicability to the most diverse Types of items as a result of the various possible and preferred embodiments of the invention, well suited for the simultaneous generation of a large number of objects, easy handling due to reliable function, low manufacturing costs due to relatively simple construction, etc.

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Claims (37)

Claims S Injection mold with hot mold inlet, with a constant high temperature held hot runner block, which has an opening for the supply of molten Resin, which communicates with channels and gates, one on lower Temperature-maintained cavity block, which the mold cavities with respective pouring openings for the molten resin, the hot runner block and the cavity block are movable relative to one another in such a way that at least during the injection the Gates of the hot runner block and the pouring openings of the cavity block are set against one another and that after the injection is completed, the gates and the pouring openings be moved apart again, d u r c h e k e n n n z e i c h -n e t that a gate temperature recovery block (30) is provided against which the gates (13) surrounding surfaces (15) can be applied in at least part of the time span, in which the gates (13) and the inflow openings (21a) do not rest against one another. 2. Injection mold according to claim 1, characterized in that the Movement of the hot runner block (10) and cavity block (20) relative to each other takes place simultaneously with the opening and closing movement of the mold. 3. Injection mold according to claim 1 or 2, characterized in that the cavity block consists of at least two halves, one of which is a stationary side Cavity block (20a) and the other is a movement-side cavity block (20), that the hot runner block (10) by means of a fastening block (4) to one of the both tool plates of the injection molding machine is attached that the stationary side Cavity block (20a) attached to the fastening block (4) so that it can move freely within limits is, and that the movement-side cavity block (20) on the other die plate (5) the injection molding machine is attached. 4. Injection mold according to claim 3, characterized in that the Connection between the stationary-side cavity block (20a) and the fastening block (4) has at least one stop (7) which is the distance by which the fastening block and the stationary side cavity block are movable apart, limited, and that a device (spring 6) is provided between the two parts (20a, 4) exerts a force that is large enough to allow relative movement in the opening direction of the shape. 5. Injection mold according to claim 4, characterized in that the Has a device for exerting a force at least one spring (6). 6. Injection mold according to claim 4, characterized in that the Device for exerting a force from a piston cylinder -Unit consists. 7. Injection mold according to one of the preceding claims, characterized characterized in that the gate temperature recovery block (30) on part of the stationary-side cavity block (20a) is attached in such a way that the gates (13) surrounding surface areas of the hot runner block (10) during the opening process of the mold come into contact with the gate temperature recovery block (30). 8. Injection mold according to one of claims 1 to 7, characterized in that that a device is provided that the relative movement of the hot runner block (10) and the cavity block independent of the opening and closing operation of Performs form. 9. Injection mold according to claim 8, characterized in that the Hot runner block (10) is attached to a mounting block that is independent of the opening and closing movement of the mold is movable, and at one of the Tool plates of the injection molding machine can be mounted. 10. Injection mold according to claim 8, characterized in that the Moment at which the gates (13) of the hot runner block (10) and the l'input openings (21a) are shifted against each other and come out of alignment in the time span between a moment immediately after the injection is stopped and a moment falls immediately before the start of opening the mold. 11. Injection mold according to claim 9, characterized in that the Relative movement of the hot runner block (10) and the fastening block (4) the movement of an injection nozzle (1) of the injection molding machine takes place. 12. Injection mold according to claim 11, characterized in that the Hot runner block (10) is attached to the nozzle (1) of the injection molding machine. 13. Injection mold according to claim 11, characterized in that a Clamping device (8) is provided which the hot runner block (10) in the direction of presses the nozzle (1) of the injection molding machine. 14. Injection mold according to claim 13, characterized in that the Tensioning device contains at least one spring (8). 15. Injection mold according to claim 13, characterized in that the Clamping device consists of a piston-cylinder unit. 16. Injection mold according to claim 9, characterized in that the Temperature recovery block (30) in a recess in the mounting block (4) is attached, into which the hot runner block (10) after completion of the injection is withdrawn. 17. Injection mold according to one of the preceding claims, characterized characterized in that the gate opening surface (15) of the hot runner block (10), in the into the gates (13) open ~ and the surface (25) of the cavity block (20), in which open into the pouring openings (21a), both in the direction of movement of the Run hot runner block (10) and the cavity block (20) relative to each other. 18. Injection mold according to one of claims 1 to 17, characterized in that that the gates (13) surrounding surface (15) of the hot runner block (10) and the The surface (25) of the cavity block (20) surrounding the pouring openings (21a) to the direction in which the hot runner block (10) and the cavity block (20) are relative to one another move, run obliquely. 19. Injection mold according to one of claims 1 to 16, characterized in that that the surface (15) of the hot runner block surrounding the gates (13) and that of the pouring openings (21a) of the cavity block (20) surrounding surface (25) at right angles to that direction run in which the hot runner block (10) and the cavity block (20) relative to one another be moved. 20. Injection mold according to claim 17 or 18, characterized in that that the gates (13) surrounding surface (15) of the hot runner block (10) on which the Surface (25) of the cavity block (20) into which the pouring openings (21a) open, at the time of injection, and that both surfaces (15, 25) are essentially flat are. 21. Injection mold according to claim 17 or 18, characterized in that that a main channel (12a) passes through the hot runner block (10) in the longitudinal direction, and that two flat door opening surfaces (15) substantially parallel to the main inlet channel (12) and facing in opposite directions, with each of the door opening surfaces (15) gates (13) open into it. 22. Injection mold according to claim 17 or 18, characterized in that that that part of the hot runner block (10), into himself the gates (13) open, cylindrical or conical in shape, and that several gates (13) into the peripheral surface of the cylindrical or conical portion of the hot runner block (10) open. 23. Injection mold according to one of the preceding claims, characterized characterized in that the door temperature recovery block (30) is a heating device (34). 24. Injection mold according to claim 23, characterized in that the Gate temperature recovery block (30) includes a device that it on a maintains a predetermined constant high temperature. 25. Injection mold according to claim 23 or 24, characterized in that that the gate temperature recovery block (30) is made of metallic material. 26. Injection mold according to one of the preceding claims, characterized characterized in that the gate temperature recovery block is made of heat insulating Material. 27. Injection mold according to claim 26, characterized in that the Gate temperature recovery block (30) made of a composite material in the form of a thin Metal film is made on the sliding surface of the heat insulating material. 28. Injection mold according to one of the preceding claims, characterized characterized in that the gate temperature recovery block (30) on the gate opening surface (15) of the hot inlet block (10) rests and the gates (13) can close. 29. Injection mold according to one of the preceding claims, characterized characterized in that the door temperature recovery block (30) is on an outer surface of the hot runner block (10) in a different area than on the door opening surface (15) is able to lie. 30. Injection mold according to one of the preceding claims, characterized characterized in that the gate temperature recovery block (30) is controlled by a jig (31) is resiliently pressed against the hot runner block (10) when both blocks (10, 30) come into mutual contact. 31. Injection mold according to one of the preceding claims, characterized characterized in that part of the hot runner block (10) is in the form of a plurality of rod-shaped Has parts (18) which are in the path of movement of the cavity block (20a) and the hot runner block (10) protrude relative to each other, and that the end faces of the rod-shaped parts (18) are designed as a gate opening surface (15) into which the gates (13) open. 32. Injection mold according to claim 31, characterized in that the end area of the rod-shaped part (18) located in the vicinity of the end face has a larger diameter than the central area of the rod-shaped part, that the gate temperature recovery block (30b) is arranged such that it is at least is level with the middle area at the time of injection and in contact can be brought with the thicker outer area of the rod-shaped part, wherein the gates of the hot runner block (10) at a distance from the pouring openings (21) of the cavity block (20). 33. Injection mold according to claim 32, characterized in that each of the rod-shaped parts (18) of the hot runner block (10) such a reverse has a conical shape that the diameter decreases towards the end at which the Gate (13) is arranged, while that part of the gate temperature recovery block (30b) which can be brought into contact with the rod-shaped part, a bore with an inverted frustoconical surface, that of the inverted frustoconical Surface of the rod-shaped part is adapted to a stable contact of the rod-shaped Part (18) to ensure with the gate temperature recovery block. 34. Injection mold according to claim 31 or 32, characterized in that that the gate temperature recovery block (30b) consists of a hollow cylindrical body consists through which the rod-shaped part (18) passes, and the wall of which is axial Has slots which are pushed apart by the rod-shaped part (18) can to ensure a firm surface contact between the rod-shaped part and the Achieve gate temperature recovery block. 35. Injection mold according to claim 31 or 32, characterized in that that the gate temperature recovery block (30) has a support part (30a) and several Having contact elements (30b) which are attached to the corresponding rod-shaped parts of the hot runner block, each contact element (30b) on the carrier (30a) substantially perpendicular to the line along which the hot gate block (10) and the door temperature recovery block (30) move relative to one another, is movably attached. 36. Injection mold according to claim 31 or 33, characterized in that that the gate temperature recovery block has a support element (30a) and contact elements (30b) on the corresponding rod-shaped parts (18) of the hot runner block (10) can rest so that the contact parts on the support element (30a) can be moved within limits are mounted and the direction of movement of the direction of relative movement between corresponds to the hot inlet block (10) and the gate temperature recovery block (30), and that the contact parts (30b) by a clamping device (31) resiliently against the corresponding rod-shaped parts (18) are pressed when they are in contact with them. 37.Injection molding process in which that part of a hot runner block, which is arranged around gate openings is kept at a high temperature and brought into contact with a cold cavity block in an injection step is so that the molten resin cools in the gate area and at least in that Moment hardened in which the injection step is finished, so that the flow in this Moment is ended and in which the area of the hot runner block surrounding the gate openingz after completion of the injection step from the cavity block is removed, d a it is noted that a door temperature recovery block brought into contact with the area of the hot runner block surrounding the gate openings is so that the hardened resin in the gate area is heated and melted again and the resin flow will flow again for the next batch of injection.