MOLD CLOSING UNIT FOR AN INJECTION MOLDING MACHINE

Abstract

The invention relates to a mold closing unit (10) for an injection molding machine for processing plastics and other compounds that can be plasticized, such as ceramic and pulverous compounds. Said mold closing unit comprises at least one machine bed (20), at least one stationary platen (14), and at least one platen (16) that can be moved relative to the stationary platen (14) by means of a drive mechanism (44), wherein the movable platen (16) can be moved on a slide (22) having guide shoes (26) along at least one guide (24) attached to the machine bed (20), and the drive mechanism (44) has at least one gear rack drive (38) driven by at least one drive motor (32). Because at least two gear racks (34) are fixedly connected to the machine bed (20) and because the drive motor (32) is fixedly connected to the slide (22) and, in the event of a movement of the movable platen (16), moves synchronously with the movable platen (16) in the same direction, occurring tilting torques are reduced and safe operation of the mold closing unit is ensured.

Claims

1.-12. (canceled)

13. Mold closing unit for an injection molding machine for processing plastics materials and other plasticizable materials such as ceramics and powdered materials, comprising at least one machine bed, at least one stationary mold mounting plate arranged on the machine bed, at least one movable mold mounting plate arranged on the at least one machine bed movable relative to the at least one stationary mold mounting plate, wherein the at least one movable mold mounting plate is movable on a carriage with guideway shoes along at least one guideway that is mounted on the at least one machine bed with the at least one stationary mold mounting plate into and out of closure of an injection mold arrangeable in a mold clamping space, at least one drive mechanism for moving the at least one movable mold mounting plate and for opening/closing the mold closing unit, wherein at least one the drive mechanism has at least one toothed rack drive driven by at least one drive motor with at least one gearwheel and at least one toothed rack cooperating therewith, wherein at least two toothed racks are fixedly connected to the at least one machine bed and wherein the at least one drive motor is fixedly connected to the carriage and during a movement of the at least one movable mold mounting plate moves synchronously with the at least one movable mold mounting plate in the same direction, wherein the carriage comprises at least one load sensor for detecting tilting forces, which at least one load sensor is connected to at least one regulating unit, which is adapted to regulate the at least one drive mechanism according to the tilting force.

14. Mold closing unit according to claim 13, wherein the at least one drive mechanism is arranged in a plane of the machine bed.

15. Mold closing unit according to claim 13, wherein the at least one drive motor is intended and suitable both for moving the at least one movable mold mounting plate and also for opening and closing the mold closing unit.

16. Mold closing unit according to claim 13, wherein, for applying the closing force on closure of the injection mold, there is provided a closing force generating unit, decoupled from the at least one drive mechanism.

17. Mold closing unit according to claim 16, wherein the closing force generating unit is mounted on the at least one stationary mold mounting plate.

18. Mold closing unit according to claim 13, wherein the at least one load sensor is arranged in the support of the force application points of the at least one movable mold mounting plate.

19. Mold closing unit according to claim 13, wherein the at least one drive mechanism comprises at least one brake.

20. Mold closing unit according to claim 13, wherein the at least one drive mechanism comprises at least two drive motors which engage independently of one another in a toothed rack drive.

21. Mold closing unit according to claim 13, wherein the at least one drive mechanism comprises four drive motors which engage independently of one another in a toothed rack drive.

22. Mold closing unit according to claim 13, wherein the at least one drive mechanism comprises at least one drive motor which drives at least one shaft, which is in operative connection with at least two toothed rack drives.

23. Mold closing unit according to claim 13, wherein the toothed racks are arranged beneath the guideway for the at least one movable mold mounting plate.

24. Mold closing unit according to claim 23, wherein the toothed racks are covered by the guideway for the at least one movable mold mounting plate.

25. Mold closing unit according to claim 11, wherein adjusting means are provided for adjusting the at least one movable mold mounting plate, on one side, on the guideway, on the other side, on the at least one toothed rack.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0030] The disclosure will now be described in greater detail by reference to an exemplary embodiment illustrated in the accompanying figures. In the drawings:

[0031] FIG. 1 shows an isometric view of the mold closing unit according to the disclosure in the opened state from obliquely above,

[0032] FIG. 2 shows a rear view of the mold closing unit according to FIG. 1,

[0033] FIGS. 3a-3c show side views of the mold closing unit according to FIG. 1 in different exemplary embodiments with different drive concepts,

[0034] FIG. 4 shows a sectional view of the drive mechanism in the region of the machine bed with two drive motors, along the line B-B in FIG. 3a,

[0035] FIG. 5a shows a rear view of the mold closing unit with a drive motor and a shaft,

[0036] FIG. 5b shows a rear view according to FIG. 5a in a further exemplary embodiment with a double drive having a continuous shaft.

DETAILED DESCRIPTION

[0037] The disclosure will now be described in greater detail making reference to the accompanying drawings. The exemplary embodiments merely represent examples, however, which are not intended to restrict the inventive concept to a particular arrangement. Before the disclosure is described in detail, it should be noted that it is not restricted to the various components of the device and the various method steps, since these components and methods can vary. The expressions used here are intended merely to describe particular embodiments and are not used restrictively. Furthermore, where the singular or the indefinite article is used in the description or the claims, it also relates to a plurality of these elements, provided the overall context does not clearly reveal otherwise.

[0038] FIG. 1 shows schematically a perspective view of a mold closing unit 10 from obliquely above for an injection molding machine for processing plastics and other plasticizable materials such as ceramic or powdery materials, comprising a stationary mold mounting plate 14, a movable mold mounting plate 16 which, together with the stationary mold mounting plate 14, defines a mold clamping space R for receiving changeable injection molds 12, as shown partially in FIG. 1.

[0039] The movable mold mounting plate 16 is mounted on a carriage 22 with guideway shoes 26 and is movable, along at least one guideway 24 mounted on the machine bed 20, relative to the stationary mold mounting plate 14 into and out of closure of an injection mold 12 arranged in the mold clamping space R. Bars 18 engage through the movable mold mounting plate 16 and, in the closed state, lock the mold closing unit 10 or the stationary mold mounting plate 14 to the movable mold mounting plate 16. In order to move the movable mold mounting plate 16 and for opening/closing the mold closing unit 10, the mold closing unit 10 has at least one drive mechanism 44. The drive mechanism 44 comprises at least one toothed rack drive 38 driven by at least one drive motor 32 with at least one gearwheel 36 and at least one toothed rack 34 cooperating with the gearwheel according to FIG. 4.

[0040] According to the rear view of the mold closing unit in FIG. 2, at least two toothed racks 34 are firmly connected to the machine bed 20. The drive motor 32 is firmly connected to the carriage 22. On actuation of the drive mechanism 44, the drive motor 32 rotates the gearwheel 36 which engages into the toothed rack 34 and thereby moves the carriage 22. During a movement of the movable mold mounting plate 16, the drive motor 32 moves synchronously with the movable mold mounting plate 16, in the same direction. The drive motor 32 moves together with the movable mold mounting plate 16. Preferably, an even number of toothed racks 34 is provided.

[0041] Advantageously, the drive mechanism 44 is arranged in the plane E of the machine bed 20 and preferably beneath the support elements for the mold mounting plates, so that free access to the mold clamping space R is provided. Thereby, the toothed racks 34 are preferably mounted on the machine bed 20 in suspended manner and located internally and thereby protected against dirt.

[0042] In principle, however, another arrangement of the drive mechanism 44, for example, laterally to or above the mold mounting plates 14, 16 is also conceivable. The toothed rack 34 could then be supported, for example, on the stationary mold mounting plate 14.

[0043] The at least one drive motor 32 is preferably intended and suitable both for moving the movable mold mounting plate 16 and also for opening and closing the mold closing unit 10. Separate drives are not needed for these movement processes.

[0044] The closing force to be applied during closure of the injection mold 12 and during injection of the plasticizable material into the mold cavity is preferably applied by means of a separate closing force generating unit 50 which is preferably mounted on the stationary mold mounting plate 14 or on another stationary element of the machine, for example, a support plate for the mold closing unit. As a result, a separate decoupling of the mold travel movement and the closing force application is not needed. The element for the application of the closing force can thus be actuated directly at any time and without delay, which reduces the cycle time of the cyclically operating injection molding machine.

[0045] FIG. 2 also shows that the toothed racks 34 are arranged beneath the guideway 24 and preferably covered by the guideway 24 for the movable mold mounting plate 16. For further stabilization, adjusting means 46 can be formed in the exemplary embodiment by a slotted adjustment of the motor/pinion combination for adjusting the movable mold mounting plate 16 on the guideway 24 on the one side and, on the other side, on the toothed rack 34, in order thereby to achieve a play-free adjustment between the guiding system and the drive system.

[0046] In a further exemplary embodiment according to FIG. 3a, load sensors 40 are mounted on the carriage 22. In principle, the load sensors 40 being mounted directly on the movable mold mounting plate 16 is also conceivable, as is a mounting of the load sensors 40 on the carriage 22 and the movable mold mounting plate 16. With the aid of the load sensors 40, tilting forces affecting the movable mold mounting plate 16 are detected. The tilting forces can lead to an inclination of the movable mold mounting plate 16 in and/or against the movement direction not only, but also due to an uneven load distribution during the movement, in particular during the acceleration of the movable mold mounting plate 16.

[0047] Given knowledge of the load distribution, the tilting forces are preferably be compensated for with a regulating unit C. For this purpose, the load sensors 40 are connected to the at least one regulating unit C which regulates the drive mechanism 44 according to the tilting forces present so that a tilt-free movement of the movable mold mounting plate 16 and, as far as possible, a plane-parallel movement of the mold mounting plates relative to one another can be assured. With the aid of the load sensors 40, tilting forces occurring during operation of the injection molding machine or of the movable mold mounting plate 16 can be detected. The regulating unit C subsequently regulates the drive mechanism 44 according to the detected tilting forces so that the tilting forces are compensated for by acceleration or braking of the movable mold mounting plate 16. For example, in the presence of a tilting force in the movement direction of the movable mold mounting plate 16 the regulating unit C can briefly increase the speed of the gearwheel drives 38 by means of the drive mechanism 44, in order to intercept and compensate for a tilting of the movable mold mounting plate 16.

[0048] If four drives are provided, the movable mold mounting plate 16 can be displaced or moved in a restrained manner, i.e. it is determined by its degrees of freedom.

[0049] FIGS. 3b and 3c show alternative drive concepts. Whilst in FIG. 3b, a plurality of drives are regulated by a regulating unit C, FIG. 3c shows a solution in which each drive is regulated by a separate regulating unit C. This therefore involves an independent control system and the regulating units can communicate with one another for stabilising the mold mounting plate 16.

[0050] FIG. 4 shows a sectional view of the drive mechanism 44 in the region of the machine bed 20 along the sectional plane B-B shown in FIG. 3a. In order to decelerate the movable mold mounting plate 16, the drive mechanism 44 comprises at least one brake, preferably as a stopping brake or an emergency stop brake. In FIG. 4, the drive mechanism 44 preferably comprises a brake 30 which is mounted centrally between the drive motors 32. Alternatively or additionally, a further brake 28 can be provided. All the brakes can be configured as frictional brakes or as locking brakes, dependent upon their location and configuration. The brakes 30 and 28 assume, in principle, the same function (emergency stop or stopping brake), wherein merely alternative positions have been shown. Also conceivable, for example, is a hydraulic brake. Provided to the left and the right beside the drive motors 32, alternatively or in addition to the brake 30 is a further brake 28, each of which is associated with a toothed rack drive 38. Furthermore, the brakes 28, 30 can secure the toothed rack drives 38 so that the movable mold mounting plate 16 can no longer be moved. In the exemplary embodiment, at least one or a combination of up to six brakes can be implemented (a maximum of 2 brakes in the middle (position 30) and one each at right and left (position 28) and/or two brakes at each of right and left (position 28).

[0051] In FIGS. 3a and 4, the drive mechanism 44 comprises two drive motors 32, each being associated with a toothed rack drive 38. The drive motors 32 are preferably arranged to left and right of the brake 30 and drive respective gearwheels 36 which engage in the toothed racks 34 and so move the carriage 22. The drive motors 32 can drive the toothed rack drives 38 synchronously or can also operate independently of one another. For example, it is possible during a tilting of the movable mold mounting plate 16, to actuate both drive motors 32 simultaneously synchronously in their movement direction in order thus to compensate for the tilting. Furthermore, in the case of a lateral right-left tilting of the movable mold mounting plate 16, it is possible to actuate the right and/or left toothed rack drive 38 and so to restore the parallelism of the movable mold mounting plate 16 in relation to the stationary mold mounting plate 14.

[0052] In a further preferred exemplary embodiment according to FIG. 5a, the drive mechanism 44 comprises a drive motor 32 which drives the two toothed rack drives 38 by means of a shaft 42 via the gearwheels 36. By this means, a parallel driving of the movable mold mounting plate 16 is ensured. FIG. 5a also shows a centrally arranged brake 30.

[0053] During a tilting of the movable mold mounting plate 16 in the movement direction of the movable mold mounting plate 16, it is possible, by actuating the toothed rack drive 38, to compensate for the tilting and to bring the movable mold mounting plate 16 into parallelism with the stationary mold mounting plate 14. For this purpose, a double drive 32 is provided in FIG. 5b with a continuous shaft 42 for driving two gearwheels 36.

[0054] In principle thereby, a motor with, for example, two gearwheels 36 that are connected to a continuous shaft 42 can engage in two toothed racks (FIG. 5a). This is also possible with a plurality of motors according to FIG. 5b. Similarly, according to FIGS. 3b and 3c, a plurality of, for example four, motors with each of which a gearwheel driven by the motor is associated can engage, for driving, in two toothed racks.

[0055] It is self-evident that this description can be subject to a great variety of modifications, amendments and adaptations, which belong within the scope of equivalents to the accompanying claims.