SK287853B6 - Device for injection molding of plastic items - Google Patents

Abstract

There is disclosed a device for injection molding of plastic items, comprising an injection machine (1) and a tool (2) belonging to it, where in this tool (2) there are at least two cavities (11, 12), which correspond to dimensions of produced plastic moldings. The tool (2) comprises at least three parts (4, 5, 6), which are able to be moved relative to one another, the frontal part (4), the middle part (5) and the rear part (6), which firmly adjoin each other along parting planes (9,10) extending parallel one to each other, during operation of a pressure generator (8) in operating condition. In the tool (2), there is performed at least one channel (13) for supplying molten plastic and ending on one side in the cavities (11, 12) and on the other side at an inlet point (14) on the surface of the tool (2). During operation, said point (14) is connected to the injection machine (1), at which is on the parts of the tool (2) provided a locking, adjustable between two terminal positions, by which are locked at first end position, while the pressure generator (8) is disconnected, only the middle part (5) and the frontal part (4) of the tool (2), provided with the inlet area (14), and at second end position only the middle part (5) and the rear part (6) of the tool (2). On the middle part (5) of the tool (2), there is provided at least one driving mechanism (19) with at least one slide valve (18) running in the tool (2) axis direction, which can be adjusted by the driving mechanism (19) in two opposite directions in its longitudinal direction between two end positions. On the tool (2), there is further provided in an area of each parting plane (9, 10) at least one clamping device (K), of which first part is always positioned in the middle part (5) of the tool (2), while the second part, which interacts with the corresponding first part, is secured on one side to the frontal part (4) of the tool (2) and on the other side to the rear part (6) of the tool (2). At least one holder (20, 21) functioning as a second part of the clamping device (K) and extending in the tool (2) axis direction is secured to the frontal part (4) and to the rear part (6) of the tool (2). When the tool (2) is closed, said holder (20, 21) encroaches by its one end in the corresponding first part of the clamping device (K) and at this end it is provided with at least one clamping body (R). The slide valve (18) encroaches in one of its end positions to a locking control element of the clamping body (R) to corresponding clamping device (K).

Description

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for injecting plastic fittings comprising an injection molding machine and a tool associated therewith, wherein at least two cavities are provided in the tool corresponding to the dimensions of the fittings produced. a front piece, a middle piece and a rear piece which, when the pressure exerting device is in the working position, are fixedly adjacent to each other along the dividing planes which run parallel to each other and in which the tool has at least one molten plastic supply channel terminating at one in the cavities and on the other hand at an entry point on the surface of the tool, which in the working position is connected to the injection molding machine, in which the tooling is provided with a lock adjustable between the two end positions. only the middle and the front part of the tool, which is provided with an entry point, and in the second end position only the middle and the rear part of the tool (German magazine "Kunststoffe 84" (1994) 10, pages 1375 to 1382).

BACKGROUND OF THE INVENTION

Injection molding machines are used for the production of fittings with almost any shape.

Only cavities into which molten plastic can be injected must be available in the respective tool. The tool parts separated by a separating plane are compressed together, for example hydraulically, in the working position. After the plastic has been injected into the tool cavities, the tool remains closed in the prior art for as long as the fittings in the cavities have sufficiently cooled and are thus strengthened so that they can be removed from the tool. To do this, the tool opens in the dividing plane, whereby its parts are separated from each other. The injection molding machine is not used during the time during which the plastic of the fittings is cooled in the cavities. This disadvantage is particularly serious when relatively thick-walled fittings with a long cooling time are to be produced.

The performance of the injection molding machine can be increased when using a tandem working tool according to the aforementioned German magazine "Kunststoffe 84". In an injection molding machine working with such a tool, the parts open alternately in two parting planes. During the cooling period of the fittings of one separation plane, the fittings can be removed from the other separation plane from the mold. This method of operation is advantageous for fittings with a cooling time that is longer than the dosing time required to fill the cavities. Tandem injection molding machines are expensive special machines. They require a movable center plate located in a central position to which the injection unit is laterally connected. The molten plastic is injected through the channels arranged in the center plate into the respective cavities. This known tandem method cannot be used in conventional injection molding machines or can only be used after extensive conversions.

DE 101 10 611 of the same applicant discloses a range device according to the introductory paragraph of this description.

SUMMARY OF THE INVENTION The object of the invention is to improve the aforementioned apparatus in such a way that the production of finished fittings can be easily increased even when using conventional injection molding machines with a secure locking of those separating planes which are not to be opened.

SUMMARY OF THE INVENTION

This blocking task is accomplished by a plastic injection molding device consisting of an injection molding machine and a tool associated therewith, in which at least two cavities are provided in the tool, corresponding to the dimensions of the fittings produced, in which the tool consists of at least three relative to each other. movable parts, front, center and rear, which, when the pressure exerting device is applied in the working position, adhere to one another and run parallel to one another along the separating planes, and in which at least one molten plastic supply channel is formed in the tool in the cavities and, on the other hand, at an entry point on the tool surface which, in the working position, is connected to the injection molding machine, in which the tool parts are locked, adjustable between the two end positions which are locked together when the pressure generator is disconnected in the first end position only the middle part and the front part of the tool containing the entry point, and in the second end position only the middle part and the rear part of the tool, which according to the invention consists in providing at least one drive with at least one sliding drive a switch extending in the direction of the tool axis, which is adjustable by drive in two opposite directions in its longitudinal direction between the two end positions, and furthermore, in that at least one clamping device is provided on the tool in each region in each case the first part is positioned on the middle part of the tool, while the second part, which cooperates with the corresponding first part, is fixed on one side to the front part of the tool and on the other side to the rear part of the tool; a tool part fixed as a second part of the clamping device at all times at least one holder extending in the direction of the tool axis which, when the tool is closed, engages one end in the corresponding first part of the clamping device and is provided with at least one clamping body at this end, and that the slide switch in each of its end positions interferes with the clamping control into the corresponding clamping device.

This blocking is particularly simple. It consists essentially of a drive with a slide switch and two clamping devices in which the slide switch alternately intervenes. In order to effect an effective locking between two tool parts in each case, the sliding switch needs to be pushed by the drive into only one of the clamping devices so that their clamping body is moved to the closing position. In the respective closing position, the slide switch is pulled out of the clamping device lying in the region of the respective second cutting plane, so that the tool can be opened in this cutting plane.

Said device is further advantageously designed so that two separate clamping devices and two sliding switches are formed on the tool in the region of each cutting plane.

In an even more preferred embodiment of the device, at the ends of the holders which engage the corresponding parts of the clamping devices in the locked position of the tool, at least one transversely clamping body extending in the locked position extends beyond the fixed stop forming the first part of the clamping device. mounted on the middle part of the tool.

In an even more preferred embodiment of the device, the clamping body is formed as a roller rotatable freely about its axis.

In an even more preferred embodiment of the device, a clamping body is always provided on the two opposite sides of the holder, and two corresponding stops are always fixed on the middle part of the tool.

The drive may advantageously be controlled automatically. This can be done by pneumatically or electrically operating drive. Preferably, however, a hydraulic drive is used.

The lock, consisting of the drive with the slide switch and the clamping devices, can advantageously be positioned to save space inside the tool profile. In this case, the locking parts will not increase the external dimensions of the tool. Depending on the size of the tool, at least two latches are preferably located on two opposite sides of the tool.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the invention will be explained in more detail by means of the exemplary embodiments shown in the drawings. The figures show the following:

Fig. 1 is a partial cross-sectional view of the device according to the invention in the closed position, FIG. 2 and 3 are two different open positions of the device of FIG. 1, FIG. 4 is a principle view of the blockage used in the apparatus; FIG. 5 in relation to FIG. 4 shows a supplementary embodiment of the device, FIG. 6 and 7 are the devices of FIG. 5, in the corresponding open positions of FIG. 2 and 3, FIG. Fig. 8 is an enlarged view of a holder usable in the apparatus; 9 is a cross-sectional view of the holder of FIG. 8 along the plane IX-IX.

In the drawings, only those parts of the injection molding device which are necessary for understanding the invention are shown. Basically known elements of the device, such as an opening and closing mechanism or cooling ducts, or a heating device, are not shown. In FIG. 4 to 7, for greater clarity, the dashing of parts in cross-section is omitted.

DETAILED DESCRIPTION OF THE INVENTION

The injection device of FIG. 1 consists of an injection molding machine 1 and a tool attachable thereto

2. The injection molding machine I can be a conventional, usually sold machine without any special equipment. The machine is movable in the direction of the double arrow 3.

The tool 2 consists of three parts, a front part 4, a middle part 5 and a rear part 6. It is closed on the rear part 6 by a pressure plate 7, which is connected to a pressure generator 8. For example, a pressure or hydraulic press can be used. The three parts of the tool 2 are separated from each other by two parallel planes 9 and 10 running parallel to one another.

At least one cavity 11 and 12, respectively, of the tool 2 can be formed in each of the dividing planes 9 and 10, the clear dimensions of which correspond to the geometric shape of the shaped pieces produced. In the embodiment shown, two cavities 11 and 12 are shown for each of the dividing planes 9 and 10, respectively.

In the illustrated embodiment, a channel 13 is centrally formed in the tool 2, which serves to supply molten plastic to the cavities 11 and 12. The channel 13 begins at an outwardly open entry point 14 lying on the surface of the tool 2. In order to be able to be referred to as a spout, the plastic material can be removed from the channel 13 after cooling and molding and its removal from the mold, this channel 13 correspondingly formed as conical in both sections as shown in the drawing. Partial channels 15 and 16, respectively, extend from channel 13 and lead to cavities 11 and 12, respectively. Partial channels 15 and 16 lie preferably in the divider planes 9 and 10.

The device according to the invention is shown in FIG. 1 in the operating position. For example, it works as follows:

The three parts 4, 5 and 6 of the tool 2 lie close together in the working position. They are pressed together by a pressure exerting device 8 against the support plate 17 serving as a fixed support on which the front part 4 of the tool 2 is located. To produce the fittings in the cavities 11 and 12, the injection machine 1 extends up to the inlet 14 and the channel 13 on the tool. 2. The molten plastic present in the injection molding machine 1 can then be pressed into the channel 13. Through the channel 13 both the partial channels 15 and 16 as well as the cavities 11 and 12 are filled. When the cavities 11 and 12 are filled using sufficient pressure, the machine 1 closes. The plastic present in the tool 2 is then cooled.

After a sufficient cooling time, the tool 2 is opened, for example, in the dividing plane 9. The parts 5 and 6 of the tool 2 remain locked together by means of a lock which is explained. After the pressure force exerted by the pressure generator 8 has been switched off, they can be brought to the position shown in FIG. 2. The locking can be carried out in such a way that after the pressure extinguishes from the pressure extinguisher 8, a residual force remains which holds together the two parts 5 and 6 of the tool 2. The molded parts produced in the cavities can now be removed from the tool. remaining in the channel 13 in the front part 4 of the tool 2, is removed, for example, by compressed air, so that this part of the channel 13 is free again.

The tool 2 is then brought back to the closed or operating position, as shown in FIG. 1, in which its parts 4, 5 and 6 are firmly pressed against each other by a pressure generator 8. The cavities 11 are refilled with plastic. Subsequently, the locking is adjusted such that the tool parts 5 and 4 are locked together as described for the parts 5 and 6. The tool 2 is then opened in the dividing plane 10, with only its rear part 6 with the pressure plate 7 displaced to the position shown in FIG. 3. It is now possible to remove the finished fittings from the cavities 12. During this time, the plastic is cooled in the cavities 11 in the dividing plane 9. The inflow located in the portion of the channel 13 which is in the middle part 5 is removed again using compressed air.

The tool 2 is then brought back into its closing or operating position, as shown in FIG. 1. The cavities are refilled with plastic and the parts 5 and 6 lock together. In the meantime, the fittings in the cavities 11 have been cooled, so that the tool 2 can be opened as described above in the separating plane 9. In this way, the cavities 11 and 12 are continuously alternately filled with plastic and after cooling the mold is removed.

In order to cool the plastic in the cavities 11 and 12, it is necessary, as already mentioned, that the two respective parts of the tool 2 always remain locked after the pressure force exerted by the pressure generator 8 has ceased. For this purpose, a lock comprising the residual force of FIG. 4 to 7, which is provided on at least one side of the tool 2, or on at least two different sides of the tool 2. The construction of the locking and the manner of its operation are described.

The blocking consists of the schematic representation in FIG. 4, in which the tool 2 of the device is shown in the cut-out in the closing or operating position, respectively, of a drive 19 equipped with a rod-shaped slide switch 18 and of two two-piece clamping devices K surrounded by a dashed line. The slide switch 18 extends in the direction of the tool axis 2. The slide switch moves in this direction between two end positions. Each clamping device K includes, as a first part, a holder 20 and 21, respectively, extending in the direction of the tool axis 2, of which the holder 20 is mounted on the front part 4 and the holder 21 is mounted on the rear part 6 of the tool 2.

As the second parts of the clamping devices K, they are fixed to the central part 5 of the tool 2 in each case in the region of the dividing planes 9 and 10 on one side of the stop 22 and 23 and the stops 24 and 25 on the other side. At least one stop on the clamping device K should always be provided. The distance between the stops always corresponds to the width of the holder 20 and 21, respectively, which, as the first part in the respective locking position of the tool part, protrudes into the corresponding second part. slips between the two stops. Each holder 20 and 21, respectively, have at their free end two clamping bodies R, at least one clamping body R being to be provided, which are displaceable transversely to its respective longitudinal direction on or in the respective holder.

The clamping bodies R are in the form of rollers and are freely rotatable as well as adjustable laterally, transversely to the direction of the tool axis 2, and located on the respective holder 20 and 21 respectively. In the rest position they lie in the profile of the holders as shown in FIG. 4 on the right side for the holder 20 and are moved outwardly by the sliding switch 18 so that, in the locked position of the tool 2, they engage the stops as shown in FIG. 4 on the left for holder 21 and stops 24 and 25.

The slide switch 18 is slidable in the directions of the double arrow 26, i.e. in opposite directions between the two end positions. In one, in FIG. 4, the slide switch 18 engages the clamping device K in the region of the dividing plane 10 so that the middle part 5 and the rear part 6 of the tool 2 are locked together. In addition, the slide switch 18, as already mentioned, has moved the rollers R out of the holder 21 so that they now lie behind the stops 24 and 25. Since the rollers R are mounted in the holder 21 as freely rotatable and movable laterally, When the holder 21 is pulled out of the stops 24 and 25, the slide switch 18 is moved back to its rest position in the respective holder as shown for the holder 20.

The interaction of the clamping devices K and the slide switch 18 will be explained by way of example with reference to FIG. 8 and 9, in which the end of the holder 20 is enlarged,

At the end intended to interfere with the clamping device K, the bracket 20 has a slotted cutout 27 extending in its longitudinal direction, approximately in the middle, into which the slide switch 18 engages in the locked position of the clamping device 18. In the illustrated embodiment, the cutout 27 is open outwards at two opposite locations. Two freely rotatable clamping bodies are provided at these points, designed as rollers and movable transversely to the longitudinal direction of the holder 20. They may also be provided, on the face, with circular recesses in which the pins 28 which are attached to the holder 20 engage. In the drawing above, it is integrated into the profile of the holder 20 so that it can move around the stop 22. The lower roller is pushed out of the holder 20 by a slider 18 indicated by a broken line so that it lies in a locked position behind the stop 23.

In principle, each holder 20 and 21 requires only one clamping body R. Then only one stop is required on the tool part 5 at a time. For reasons of symmetry, however, the embodiment described with two clamping bodies R and two respective stops is advantageous. The clamping bodies R may have a different geometric shape from the roller shape mentioned above.

On each side of the tool 2 two separate clamping devices K are formed as shown in FIG. 5 for one side of the tool 2. This unduly prevents the unwanted opening of the tool 2 in the separation planes 9 and 10 during the locking phase. In this embodiment, the actuator 19 is provided with two sliding switches 18 which are mounted on a common support 29 and therefore the actuator 19 adjusts them synchronously.

The blocking described operates from the operating position of the device of FIG. 5, for example as follows:

As long as the pressure generator 8 is switched off, it will be as shown in FIG. 5 for locking the two tool parts 5 and 6 together. For this purpose, the two slide switches 18 have been moved by the drive 19 between the rollers R of the two holders 21. The tool parts 5 and 6 are thus held together by sufficient residual force. To remove the fittings from the cavities 11, the tool 2 can now be opened in the separation plane 9, as was analogous to FIG. 2 shown in FIG. 6th

After the fittings have been removed from the cavities 11, the tool 2 is closed again and the plastics are again injected into the cavities 11 under the active pressure generator 8. Prior to removal of the fittings from the cavities 12 of the separating plane 10, a locking for the front part 4 and the middle part 5 of the tool 2 is operated. The drive 19 moves the slide switches 18 to the second end position in which the slide switches 18 push the rollers R of the holders 20 outwards, This locking position of the tool 2 results in an analogous manner to FIG. 3 of FIG. 7th

Claims (5)

PATENT CLAIMS Apparatus for injection molding of plastic fittings, consisting of an injection molding machine (1) and an associated tool (2), in which at least two cavities (11, 12) are provided in the tool (2) corresponding to the dimensions of the fittings produced, in which the tool (2) consists of at least three relatively movable parts (4, 5, 6), a front part (4), a middle part (5) and a rear part (6), which are brought together by the pressure generator (8) ) in the working position, they are firmly adjacent to one another along the dividing planes (9, 10) which extend through the cavities (11, 12) perpendicular to the direction of movement of the parts and run parallel to each other, each dividing plane (9, 10) extending through the at least one cavity (11, 12), and wherein at least one molten plastic supply channel (13) is formed in the tool (2) and terminates on one side in the cavities (11, 12) and on the other side at an inlet (14) on the surface of the tool (12). 2), which is connected in working position in the injection molding machine (1), and in which a blocking is provided on the tool parts (2), which is adjustable between two end positions which only the middle part (5) is locked together in the first end position when the pressure generator (8) is disconnected and a front part (4) of the tool (2) comprising an entry point (14), and in the second position only the middle part (5) and the rear part (6) of the tool (2), characterized in that on the middle part (5) at least one actuator (19) is provided with at least one slide switch (18) extending in the direction of the tool axis (2), which is adjustable by the actuator (19) in two opposing directions in its longitudinal direction between the two end positions, further, in that at least one clamping device is provided on the tool (2) in the region of each parting plane (9, 10) 5 (K), of which the first part is always located on the middle part (5) of the tool (2), while the second part, which cooperates with the corresponding first part, is fixed on one side to the front part (4) of the tool (2) and, on the other hand, on the rear part (6) of the tool (2), in that at least one holder is always attached to the front part (4) and the rear part (6) of the tool (2) as a second part of the clamping device (K). (20, 21) extending in the direction of the tool axis (2) which, when the tool (2) is closed, engages one end in the corresponding first part of the clamping device (K) and is provided with at least one clamping body (R) the switch (18) in each of its end positions extends to the locking actuation of the clamping body (R) in the corresponding clamping device (K). Device according to claim 1, characterized in that two separate clamping devices (K) and two sliding clamping devices (K) and two sliding clamping devices (K) are provided on the tool (2) in the region of each cutting plane (9, 10). 15 switches (18). Device according to claim 1 or 2, characterized in that at the ends of the holders (20, 21) which, in the locked position of the tool (2), engage the corresponding parts of the clamping devices (K), at least one transverse to the tool axis. 2) a movable clamping body (R) which, in the locked position, engages a fixed stop (22, 23, 24, 25) forming the first part of the respective clamping device (K) and fastened to the middle part (5) of the tool (2). Device according to claim 3, characterized in that the clamping body (R) is designed as a roller rotatable freely about its axis. Device according to claim 3 or 4, characterized in that a clamping body (R) is arranged on two opposing sides of the holder (20, 21) and on the middle part (5) of the tool (2) there are 25, respectively, two corresponding stops (22, 23 and 24, 25) respectively.