DE19831271A1 - Rotary casting unit for thermoplastic parts has arm with paired and hooded mold supports turning about common longitudinal axis, and includes heating and cooling provisions - Google Patents

Abstract

The arm (33) and paired mold supports (34) carried by it, rotate about its common longitudinal axis, turned by a drive unit. Each support includes a detachable hood (36) surrounding the mold and forming a heating chamber. Preferred features: Mold supports lie opposite each other. The hood is hemispherical. On each arm, mold supports rotate on an axis penetrated transversely by its longitudinal axis. Each support includes a rack driven by a motorized pinion, its axis aligning with that of the arm. The rack is on the rear side of the support, facing the arm. Further detail and support drive variants are included. The arm is hollow and adjustable, also swinging about horizontal and vertical axes. Its height can be varied.

Description

The invention relates to the arrangement of a rotary device for rotational molding of parts made of meltable plastic with at least one working arm on which a rotatable mold carrier for receiving at least one shape is arranged with a drive device which rotates the mold carrier offset, with a heater to melt the art fabric as well as with a cooling device for the finished molded Parts.

From EP 0 177 906 A2 an arrangement of a rotation is direction became known, that with a manipulation station, with a heating chamber, with a cooling chamber and with an Ar arm for receiving at least one tool for melting or casting workpieces, especially from plastics, is provided.

This arrangement offers the possibility of plastic hollow bodies according to the shape of the tool after rotation process by melting or casting. Doing so the tool on the manipulation station with the required  Chen primary material, preferably plastic powder, filled and after closing by means of the rotating device in a Double rotation movement around two perpendicular to each other Brought axes.

The known arrangement has three star-shaped from a Zen working arms, one end of each stuff is worn. On a circle next to this center others are a heating chamber, three cooling chambers and one Manipulation station for loading and unloading the tools. Here at the filled and closed tool rotates from the first working arm pivoted into the heating chamber. Simultaneously The second arm makes another one, previously in the Tool is still rotating in the heating chamber Cooling chamber transported. Another tool is the third arm from the cooling chamber to the manipulation station on which the tool or mold is opened and the finished workpiece is removed. With this type Workpieces can be arranged in a wide variety of forms and make sizes.

However, the arrangement required for manufacturing is designed very complex, because for each tool is a dedicated drive is provided, which is fixed to the Tool is connected. This design causes besides that Effort for the individual drives, above all, an increased additional space requirement, since the tool is required together with the drive is picked up by the relevant working arm and ent is implemented accordingly. As a result, for example, a min minimum size of the heater required, which is the complete te unit, although basically only the tool is to be heated. This results in a corresponding to be heating volume of the boiler room, the heat to be expended  memenge is significantly larger than for heating the respective Mold required in the tool.

Based on this state of the art, it is the task of the He finding an arrangement of a rotary device of the entry Specify the type specified, the lowest possible energy caused effort and is easy to manufacture and one guaranteed safe function.

This object is achieved by the characterizing Features of claim 1 solved. Further advantageous next educations are specified in the subclaims.

Accordingly, the invention provides that the little at least one working arm is provided rotating around its longitudinal axis is that on the at least one working arm two mold carriers are arranged that the mold carriers in pairs towards each other are arranged and can be rotated about their central axis on the working arm leads are that the labor arm and the mold carrier from the An Drive device are loaded and that each mold carrier is provided with a removable hood that molds the encloses the attached shape and serves as a heating chamber.

The working arm is in a manner known per se from a cantilever formed which on a stationary base part, for example Stand, adjustable, preferably vertically adjustable, attached is brought. The adjustability of the working arm enables to move the mold carrier into positions that are at for example for loading with raw material or for removal the finished parts or the appropriate temperature tion is advantageous.  

Accordingly, according to an alternative embodiment, he inventive arrangement can also be provided that the Ar is swivel arm horizontally or horizontally and vertically adjustable.

According to a further embodiment of the invention, meh rere working arms are provided, which depend on the local conditions as well as the manufacturing technology requirements side by side, on top of each other or are arranged carousel-like on the base part. For this can it should be expedient to design the base part in the form of a link, similar to a chain to improve mobility to allow little space. But also one can rail-shaped base part may be provided, on which the Ar are poorly managed.

Depending on the local conditions, according to a wide Ren embodiment of the invention of the invention seen hood limited space, which initially ent as a boiler room used according to the heating device according to EP 0 177 906 A2, can also be used as a cooling device by instead of hot air is supplied with cold air and thus ensures that the product contained in the form attached to the mold carrier cooled and thus manageable.

Instead, it can also be provided that this is still called Product is removed after removing the hood and in one separate cooling bath is cooled.

According to a further variant it can be provided that the with the mold arm equipped with the working arm after the hot air supply melting process for cooling and thus Fi xation of the manufacturing state in a correspondingly provided  Immersed in the cooling bath. This cooling bath provides the necessary accelerated heat dissipation from the respective shape on the for carrier.

According to a preferred embodiment, the are facing each other arranged mold carriers opposite each other on free end of the working arm are arranged. It is ent speaking of a preferred further education that the mold carrier final hood spherically curved, preferably hemisphere shaped, trained.

To operate the mold carrier is according to an advantageous Development of the invention provided that each mold carrier has a ring gear that is driven by a motor-driven pinion is applied, the axis of rotation with the longitudinal axis of the Rota arm escapes. Here, the intervention can directly means by direct engagement of the gears, or indirectly, that means by means of a toothed belt.

The ring gear is peripheral to the working arm turned back of the mold carrier or at the circumference near the Rear arm of the mold carrier facing the working arm.

Instead of a positive coupling using a gear a toothed belt can also be used to create a frictional connection Connection may be provided.

For this, it proves to be expedient that every mold carrier has a drive surface that is driven by a motor Driving wheel is applied, the axis of rotation with the longitudinal axis of the rotating working arm is aligned.  

In this case, the driving surface is circular and on the back of the mold arm facing the working arm gers provided.

Instead, the drive surface can also be designed in the form of a band its circumference close to the back side facing the working arm te of the mold carrier may be provided.

Here, too, an indirect transfer of the Driving force can be provided by means of belt drive.

Another drive variant is based on the bieg principle seed wave, which also has the possibility of a very com compact design of the arrangement according to the invention offers a central drive motor that is flexible about the said Wave the assigned working arm (s) together with the forms carrier applied.

Instead of a flexible shaft, a gimbal can also be used Drive may be provided so as to transmit a higher torque to be able to.

As already mentioned, the heating is preferably in Gra nulatform for the intended material by means of hot air provided. In principle, an elec trical resistance heating can be provided, which in the Form or integrated into the respective mold carrier is and by means of a corresponding control device, ge if necessary, taking into account the corresponding temperature sensors, such as thermocouples, can be easily controlled is.  

With the design of a rotary casting arrangement according to the invention tion, which essentially depends on the combination with the working arm embossed heater shaped in the form of the removable hood is, in addition to a considerable reduction in space allowed - approx. 1000% - at the same time an enormous reduction - by up to 500% - of the heating energy to be used.

It also combines with the design according to the invention the advantage of shorter times per production cycle, so that a results in higher usage rates due to higher production figures.

The mold carrier formed by a plate and the hood can be adapted to the corresponding tool shapes. these can then reduced in size or in height or scope can be enlarged many times over. So far this has been limited due to the fixed dimensions of the heating chamber. At one of them Items in excess of volume had to be correspondingly larger Production plant. This investment can now more to a minimum for the hood and mold-receiving plate omitted.

As already mentioned above, the arrangement according to the invention can also be built in carousel form. This variant ge enables a virtually uninterrupted production, in which the molds can be removed from the mold every minute. Here will each working arm swung down for product removal and the reassembly.

The energy supply for heating or cooling it follows through the cavity of the working arm from the center of the carus sells out where the heating and cooling energy room are located.  

Any number of production arms can be attached to the carousel be installed. On the other hand, by reducing the Ro tationsarm achieved that large on the same system Containers of 1000-2000 are produced by the plant is installed on a correspondingly high concrete base and the rotation arm is extended if necessary.

These and other advantageous refinements and improvements gene of the invention are the subject of the dependent claims.

Using an off shown in the schematic drawing management example of the invention, the invention, advantage adhesive refinements and improvements of the invention as well special advantages of the invention explained and described be.

Show it:

Figure 1 shows a first arrangement of a Rotationseinrich device according to the invention in side view.

Fig. 2 shows a second arrangement of a Rotationseinrich device according to the invention in side view;

Fig. 3 shows a third arrangement of a Rotationseinrich device according to the invention in side view;

Fig. 4 shows a fourth arrangement of a Rotationseinrich device according to the invention in side view

Fig. 5 shows the arrangement of FIG. 4 in an oblique view.

In Fig. 1, a first variant of an arrangement 10 of a ro tationseinrichtung 11 according to the invention is shown in side view, in which a built on a base part 12 rotating or working arm 13 is provided, on which three mold carriers 14 are attached at a vertical distance from each other .

The mold carriers 14 are each arranged in pairs diametrically opposite one another at the free ends of axle carriers 15 , which connect to the working arm 13 . In the axle beams 15 drive elements, not shown, are provided, which act on the ends of the mold carriers 14 which rotate in rotation about their central axis, while the working arm 13 itself is also rotatable about its central longitudinal axis in the base part 11 and is also not shown here by a th Drive is applied.

In short, each mold carrier 14 rotates during operation of the arrangement 10 according to the invention according to the first variant, on the one hand, about its own central axis and, on the other hand, about the longitudinal axis of the working arm 13 which is offset by 90 °.

Furthermore, it is provided according to the invention that each Formenträ ger 14 is surrounded by a hood 16 which forms a heating chamber 18 together with the plate-shaped mold carrier 14 .

For this purpose, both the working arm 13 and the dar to adjoining axle carrier 15 are provided as hollow profiles, through which hot air for heating the mold carrier arranged, not shown here with the plastic pre-material therein, preferably in granulate form, is fed. After completing the melting and then closing centrifugal casting process, a gaseous cooling medium, for example cold air or nitrogen or carbon dioxide is supplied in place of hot air, which accelerates the rigidification process of the finished parts in the molds.

In Fig. 2, a second variant of an arrangement 20 of a ro tationseinrichtung 21 according to the invention is shown in side view, in which a horizontally held by two legs of a base part 22 rotating or working arm 23 is hen, on which in horizontal distance to each other together with four pairs of mold carriers 24 are attached.

The mold carriers 24 are here also arranged in pairs diametrically opposite one another at the free ends of axle carriers 25 which connect to the working arm 23 . In the axle supports 25 are not shown drive elements hen vorgese, which act on the ends of the mold carriers 24 in rotation around their central axis, while the working arm 23 itself also rotatably guided about its central longitudinal axis in the base 21 and steeply arranged by a here just if the drive is not shown in detail.

In this variant, too, each mold carrier 24 is enclosed by a hood 26 which, together with the plattenför shaped carrier 24, forms a heating chamber 28 .

For this purpose, both the working arm 23 and the adjoining axle supports 25 are designed as hollow profiles, through which hot air for heating the molds arranged on the mold support, not shown here, with the plastic pre-material therein, preferably in granulate form, is fed. After completion of the melting and then closing centrifugal casting process, the supply of hot air is interrupted and instead a gaseous cooling medium, for example cold air or nitrogen or Kohlendi oxide supplied, which accelerates the solidification process of the finished parts in the molds.

In Fig. 3, a third variant of an arrangement 30 of a ro tationseinrichtung 31 according to the invention is shown in side view, in which a horizontally held rotation or work arm 33 is provided on a base part 32 . At the free end of this working arm 33 , two diametrically opposed mold carriers 34 are attached, each of which is held by Ar working on arm 33 adjoining axle beams 35 .

In this variant, too, each mold carrier 34 is enclosed by a hood 36 , which together with the plate-shaped mold carrier 34 forms a heating chamber 38 .

In contrast to the variants shown so far, in this variant the working arm 33 is guided in a lifting device 40 , which permits vertical adjustment of the working arm 33 between an upper and a lower end position. In the upper end position, hot air is supplied through a first supply opening 37 provided in the base part.

For this purpose, both the working arm 33 and the adjoining axle supports 35 are also designed as hollow profiles, through which the hot air for heating the molds arranged on the mold carrier, not shown here, flows in with the plastic primary material therein, preferably in granular form .

After completion of the melting and subsequent centrifugal casting process, the supply of hot air is interrupted by lowering the working arm 33 from the lifting device and moving into the lower end position, where it is aligned with a second opening 39 to . A gaseous cooling medium, for example cold air or nitrogen or carbon dioxide, is supplied through this second supply opening 39 . As a result, as in the previously described variants, the rigidification process of the finished parts in the molds is accelerated.

Another special feature of the arrangement 30 shown here relates to the structural drive design of the working arm 33 and the mold carrier 34 .

While in the variants shown so far, the respective drives are accommodated in the base part and therefore cannot be seen at a side view, in the third variant shown here, a drive 42 on the lifting device 40 is provided, which both the working arm 33 and the Mold carrier 34 actuated.

In the example shown, the drive 42 is formed by a motor, preferably an electric motor, on the drive shaft of which a pinion is attached, which meshes with a ring gear 44 which is rotatably guided on the lifting device 40 and on the one hand receives the working arm 33 and on the other hand with the mold carriers 34 cooperate by having a compatible toothing on their back facing the working arm 33 , in which the ring gear 44 engages in a form-fitting manner.

In this way it is ensured that both a rotation of the arranged on the working arm 33 mold carrier 34 about its longitudinal axis and about its central axis, with only a single drive is provided.

In Fig. 4, a fourth variant of an arrangement 50 of a rotary device 51 according to the invention is shown in side view, in which, as can be seen in the view shown in Fig. 5, between the legs of a base part 52 three pivotally arranged rotary or Working arm 53 are provided, at the free ends of which a pair of mold carriers 54 is attached.

The mold carriers 54 are here also arranged in pairs diametrically opposite one another at the free ends of axle carriers 55 which connect to the working arm 53 . In the axle carriers 55 are not shown drive elements hen vorgese, which act on the ends of the mold carriers 54 in rotation around their central axis, while the working arm 53 itself also rotatably guided about its central longitudinal axis in the base part 51 and by an arranged therein, Actuator also not shown here is acted upon.

In this variant, each mold carrier 54 is enclosed by a hood 56 , which forms a heating chamber 58 together with the plattenför shaped carrier 54 .

Deviating from the variants shown so far, three fixed positions are seen in this arrangement 50 for each working arm 53 , namely a first position in which the mold carriers are loaded and unloaded, a second position in which the actual centrifugal casting takes place, and one third position, in which the finished parts are cooled together with the mold carriers 54 in a water bath 59 .

The molds can be heated here using hot air, as in the previously described variants. Then, for this purpose, both each working arm 53 and the adjoining axle carrier 55 are formed as hollow profiles, by which the hot air for heating the molds arranged on the mold carrier, not shown here, with the plastic pre-material therein, preferably in granular form.

Instead of this, however, an electrical resistance heating can also be provided, whereby the design of the arrangement 50 can be simplified, hot air being provided and the working arms not being required as flow paths for the heating medium.

As already stated in the introduction, the invention is not based on the examples shown are limited, but they are also wide right, in the subclaims and the introduction to the description refined variants possible.  

Reference list

10th

Arrangement (variant

1

)

11

Rotating device

12th

Base part

13

Labor arm

14

Mold carriers

15

Axle support

16

Hood

18th

Heating chamber

20th

Arrangement (variant

2nd

)

21

Rotating device

22

Base part

23

Labor arm

24th

Mold carriers

25th

Axle support

26

Hood

28

Heating chamber

30th

Arrangement (variant

3rd

)

31

Rotating device

32

Base part

33

Labor arm

34

Mold carriers

35

Axle support

36

Hood

37

first feed opening

38

Heating chamber

39

second feed opening

40

Lifting device

42

drive

44

Sprocket

50

Arrangement (variant

4th

)

51

Rotating device

52

Base part

53

Labor arm

54

Mold carriers

55

Axle support

56

Hood

58

Heating chamber

59

water bath

Claims (20)

1. Arrangement ( 10 , 20 , 30 , 50 ) of a rotation device ( 11 , 21 , 31 , 51 ) for the rotational molding of parts made of meltable plastic with at least one working arm ( 13 , 23 , 33 , 53 ) on which a rotatable mold carrier ( 14 , 24 , 34 , 54 ) is arranged to receive at least one mold, with a drive device which sets the mold carrier ( 14 , 24 , 34 , 54 ) in rotation, with a heating device for melting the plastic and with a cooling device for the finished molded parts, characterized in that is rotatably provided at least one working arm (13, 23, 33, 53) axis about its longitudinal, that on the at least one Ar beitsarm (13, 23, 33, 53), two mold carrier ( 14 , 24 , 34 , 54 ) are arranged so that the mold carriers are assigned to one another in pairs and are rotatably guided about their central axis on the working arm ( 13 , 23 , 33 , 53 ), that the working arm ( 13 , 23 , 33 , 53 ) and the mold carriers ( 14th , 24 , 34 , 54 ) are acted upon by the drive device and that each mold carrier ( 14 , 24 , 34 , 54 ) is provided with a removable hood ( 16 , 26 , 36 , 56 ) which supports the mold carrier ( 14 , 24 , 34 , 54 ) attached form and serves as a heating chamber ( 18 , 28 , 38 , 58 ). 2. Arrangement according to claim 1, characterized in that the mutually associated mold carriers ( 14 , 24 , 34 , 54 ) are each arranged opposite one another GE. 3. Arrangement according to claim 1 or 2, characterized in that the hood ( 16 , 26 , 36 , 56 ) is spherically curved. 4. Arrangement according to one of claims 1 to 3, characterized in that the hood ( 16 , 26 , 36 , 56 ) is hemispherical. 5. Arrangement according to one of the preceding claims, characterized in that on each Ar beitsarm ( 13 , 23 , 33 , 53 ), the two mutually associated form carriers ( 14 , 24 , 34 , 54 ) are each rotatably guided on an axis, which passes through the working arm ( 13 , 23 , 33 , 53 ) transversely to its longitudinal axis. 6. Arrangement according to one of the preceding claims, characterized in that each mold carrier ( 34 ) has a toothing which cooperates with a motor-driven pinion ( 46 ) whose axis of rotation is aligned with the longitudinal axis of the working arm ( 33 ). 7. Arrangement according to claim 6, characterized in that the teeth on the working arm ( 33 ) facing the rear of the Formenträ gers ( 34 ) is arranged. 8. Arrangement according to claim 6, characterized in that the ring gear is arranged peripherally on the periphery near the working arm ( 13 , 23 , 53 ) facing back of the mold carrier ( 14 , 24 , 54 ). 9. Arrangement according to one of the preceding claims, characterized in that each mold carrier ( 14 , 24 , 54 ) has a driving surface which is acted upon by a motor-driven driving wheel, the axis of rotation of which is aligned with the longitudinal axis of the working arm ( 13 , 23 , 53 ) . 10. The arrangement according to claim 9, characterized in that the driving surface is annular in shape on the working arm ( 13 , 23 , 53 ) facing the back of the mold carrier ( 14 , 24 , 54 ) is provided. 11. The arrangement according to claim 9, characterized in that the driving surface is band-shaped on the circumference near the working arm ( 13 , 23 , 53 ) facing the back of the mold carrier ( 14 , 24 , 54 ) is provided. 12. Arrangement according to one of claims 1 to 5, characterized in that the drive of the at least one working arm ( 13 , 23 , 53 ) and the mold carriers thereon be sensitive ( 14 , 24 , 54 ) of a flexible shaft connected to a drive motor is formed, which transmits the drive torque to the working arm ( 13 , 23 , 53 ) and the associated mold carriers. 13. Arrangement according to one of claims 1 to 5, characterized in that the drive of the at least one working arm ( 13 , 23 , 53 ) and the mold carriers thereon be sensitive ( 14 , 24 , 54 ) of a gimbal shaft connected to a drive motor is formed, which transmits the drive torque to the working arm ( 13 , 23 , 53 ) and the associated mold carriers ( 14 , 24 , 54 ). 14. Arrangement according to one of the preceding claims, characterized in that the working arm ( 13 , 23 , 33 , 53 ) is designed as a cantilever. 15. Arrangement according to one of the preceding claims, characterized in that the working arm ( 13 , 23 , 33 , 53 ) is formed by a hollow profile. 16. Arrangement according to one of the preceding claims, characterized in that the working arm ( 33 , 53 ) is arranged adjustable. 17. The arrangement according to claim 16, characterized in that the working arm ( 53 ) is pivotally arranged. 18. The arrangement according to claim 17, characterized in that the working arm ( 53 ) is arranged pivotably about a horizontal axis. 19. The arrangement according to claim 17, characterized in that the working arm ( 13 , 23 , 33 , 53 ) is arranged pivotably about a vertical axis. 20. The arrangement according to claim 16, characterized in that the working arm ( 33 ) is arranged adjustable in height.