CN117325394A - Hybrid series closed drive - Google Patents

Abstract

The invention relates to a toggle closure unit (1) for a molding machine, in particular an injection molding machine, comprising: at least one support element (2); a movable mold clamping plate (3); -a toggle mechanism (4) hinged to said at least one support element (2) and to said movable mould clamping plate (3); a fixed mold clamping plate (5); and at least two drives (6, 7); wherein the first drive (6) is in non-indirect operative connection with the crosshead (8) of the toggle mechanism (4); and the second driver (7) is kinematically arranged between the first driver (6) and the at least one support element (2); the first drive (6) has an energy store (9), in particular a hydraulic store, wherein the energy store (9) provides energy for building up the closing force and/or stores energy when the closing force is reduced.

Description

Hybrid series closed drive

Technical Field

The present invention relates to a toggle closing unit according to the features of the preamble of claim 1 and a method for mold closing and mold opening and for building up and reducing the closing force of a toggle closing unit according to the features of the preamble of claim 10.

Background

During the molding process, in particular in injection molding, the two molding tools are pressed against one another. These forming tools are fastened to fixed and movable mold clamping plates. The movable mold clamping plate is moved by a driving unit. The movement of the movable mold clamp plate is essentially divided into the movement of mold closing and mold opening and the construction and reduction of the closing force. The closing unit required for this purpose is arranged in a three-plate machine between the movable mold clamping plate and the support plate or support element. Such a closing unit is often implemented as a toggle closing unit. In a typical molding cycle, the form-locking movement is performed by the drive as quickly as possible. This movement is also known as a quick travel (Eilhub). Once the forming tools contact each other, a closing force build up is caused. This movement is also referred to as force travel. After the shaping, the closing force is again reduced and the shaping tools are separated from one another, that is to say opened, by: the movable mold clamp plate is moved away from the fixed mold clamp plate as quickly as possible. During this process or at the end of the movement or after it, the molded part is ejected from the mold and a new cycle can be started. The closing unit requires at least one drive in order to be able to perform the movement of the mold closing and mold opening and the closing force build-up and closing force reduction. There are now a number of solutions in which a closing unit with two or more drives is provided.

Document EP2456607B1 discloses one such closing unit with more than just one actuator. The ball screw drive actuates the crosshead and thus the toggle lever closing unit. A separate electric motor is additionally provided, which additionally can actuate the individual links of the toggle mechanism. These electric motors may be arranged not only between the connecting rod and the support plate or between the connecting rod and the movable mold clamp plate.

Document JPH10258451a also discloses a toggle closing unit, the crosshead of which can be moved by a ball screw drive. The core of the invention is the intermediate plate between the movable mold clamping plate and the toggle mechanism. An additional drive, in particular a hydraulic cylinder, is arranged in the intermediate plate.

Document EP3283269B1 likewise discloses a toggle closing unit. The toggle lever closing unit can be actuated by two different drives which are in operative connection in parallel with the crosshead of the closing unit. In this case, hydraulic drives on the one hand and electric drives on the other hand are involved. The electric drive is provided in particular for rapid movements of the mold closure and mold opening, that is to say for rapid strokes, while the hydraulic drive is provided in particular for movements of the closing force build-up and closing force reduction.

Documents CN108890997a and JPH08238557a disclose toggle closing units that can be operated via two drives in series.

The disadvantage of such a toggle lever closing unit is the unsatisfactory monotonous operating times, additionally necessary and costly constructional measures and the dynamic switching of the at least two drives.

A further disadvantage may be the asynchronous manipulation of the different drives, which may lead to non-parallelism of the mold clamping plates.

A further disadvantage may be that additional constructional measures are required by using two or more drives, such as additional intermediate plates, which lead to higher costs.

A further disadvantage may be that energy is wasted or insufficiently stored during monotonic run time when multiple drives connected in parallel are used. This occurs in particular when one drive has to bring about a second idle drive.

Disclosure of Invention

The object of the present invention is to provide a toggle lever closing unit which improves the prior art described above with regard to the disadvantages of the prior art described above. In particular, a toggle closure unit should be provided which reduces monotonic run time during the molding cycle.

With respect to the invention, this is achieved by the features of claim 1 by providing a toggle lever closing unit for a molding machine, in particular an injection molding machine, comprising at least one support element, a movable mold clamping plate, a toggle lever mechanism which is connected to the at least one support element and the movable mold clamping plate in an articulated manner, a fixed mold clamping plate and at least two drives, wherein a first drive is in a non-indirect functional connection with a crosshead of the toggle lever mechanism, and a second drive is arranged kinematically between the first drive and the at least one support element, wherein the first drive has an energy store, in particular a hydraulic store, wherein the energy store provides energy for building up a closing force and/or stores energy when the closing force is subtracted.

In other words, the invention relates to a toggle closing unit for a molding machine, in particular an injection molding machine, comprising at least one support element, a movable mold clamping plate, a toggle mechanism which is connected to the at least one support element and the movable mold clamping plate in a hinged manner, a stationary mold clamping plate and at least two drives, wherein the two drives are connected in kinematic series.

In other words, the invention relates to a toggle closing unit for a molding machine, in particular an injection molding machine, comprising at least one support element, a movable mold clamp plate, a toggle mechanism which is connected to the at least one support element and the movable mold clamp plate in an articulated manner, a fixed mold clamp plate and at least two drives, wherein the first drive is in indirect or indirect operative connection with a crosshead of the toggle mechanism, the second drive is in indirect or indirect operative connection with the first drive, and the support plate is in indirect or indirect operative connection with the second drive.

By means of two drives which are connected in series kinematically, these drives can be operated very dynamically and thus reduce the monotonous operating time of one cycle. For example, the cycling process may proceed as follows: the rapid closing movement of the movable mold clamping plate and the rapid travel are carried out by means of a ball screw drive up to the mold device. The ball screw drive as the second drive operates the crosshead by means of the first drive between the ball screw drive and the crosshead and thus moves the crosshead linearly along the longitudinal machine axis, so that the two forming tools come into contact with one another and form-locking occurs. The second hydraulic linear drive is now dynamically added to or connected to the electrically operated ball screw drive and thus locks the toggle lever and maintains the closing force. After plasticizing, injecting the molding compound and cooling the molding compound, the closing force can be relieved again via the first drive and the mold can be opened again by the second drive. These movements are substantially the same for all fast and force strokes.

In order to increase the energy efficiency, an energy store can be provided which can be used as a spring for the first drive and thus for the closing force build-up during the dynamic switching-on. When the closing force is reduced, a portion of the energy released at this time can be stored in the energy store. If the first drive is a hydraulic cylinder, the accumulator may be a hydraulic accumulator.

Monotonic run time is an important parameter of the molding process. The shorter the monotone run time, the shorter the time required for the shaping process and the more economical the number of shaped parts that can be produced. The monotonous operating time includes all the working processes of a molding cycle except for plasticizing, filling the mold, i.e. injecting the molding material, and cooling the molded part in the cavity of the closed molding tool. The monotonic run time essentially includes the time for mold closure, for closure force build, for closure force abatement and for mold opening and possibly for molded part ejection.

The movement belonging to the monotonic operation time is essentially a linear movement along the longitudinal axis of the machine. It can be provided here that there is essentially a hold, that is to say a short standstill of the movable mold clamping plate, or at least a significantly reduced movement speed, between the two relative partial movements, that is to say on the one hand the mold closing and closing force build-up, or on the other hand the mold opening and closing force reduction. Here, a dynamic and time-optimally coordinated switching of the drives may be very important.

A dynamic and optimally coordinated switching over time can for example play an important role when the crosshead of the toggle lever is driven via the first drive by means of a ball screw drive as the second drive with a rotating spindle. Such a ball screw drive with a rotating spindle has a large inertia which can negatively affect the monotonic running time, which can be compensated for by a first drive arranged between a second drive and the crosshead.

A non-indirect operative connection exists when forces and/or movements are transmitted directly from one structural component to a second structural component. If one of the two components is a drive, a non-indirect functional connection is present when the force transmission of the drive acts directly on the component to be driven and/or the drive moves the component to be driven directly. In other words, the manipulation, in particular the movement, of the component is initially caused by a drive directly connected to the component. Thus, manipulation, in particular movement, of the components is caused without intervening actions that are not part of the drive therebetween.

An indirect operative connection exists when forces and/or movements are transferred from one structural component to a second structural component via an operative intermediary. If one of the two structural components is a drive, an indirect functional connection exists when the force of the drive is transmitted through the functional medium to the component to be driven and/or the drive moves the component to be driven through the functional medium. In other words, an indirect functional connection exists when the drive is actuated, in particular moves, the structural component through the functional intermediary.

An interaction agent is a technical means of transferring the force and/or movement of a component to a second component. In other words, the interaction medium is a kinematic link between two structural components.

In other words, an acting intermediary is a structural component that intermediates between the driver and the second structural component to transfer forces and/or movements from the driver to the second structural component.

"B is arranged kinematically between a and C" within the scope of the invention means that motion and/or forces are transmitted from part a to part B and thus further onto part C (or vice versa).

In other words, "B is kinematically arranged between a and C" means that in a sequence of movements produced by at least three movements of at least three components, component a can move component C through component B and vice versa.

For example, an indirect operative connection is provided in a movable mold clamp plate, which can be moved by a first drive. The first drive acts on the movable mold clamp plate, wherein the toggle mechanism acts as an intermediate between the first drive and the movable mold clamp plate, both structurally and kinematically.

In some embodiments of the invention, the second drive is situated not only kinematically but also at least partially spatially between the first drive and the at least one support element.

The crosshead of the toggle mechanism can be manipulated, in particular moved, by an indirect operative connection by: the second drive, which generates the initial drive force, is operated, in particular moves, the crosshead via the first drive, which is arranged as an acting intermediate between the second drive and the crosshead. An indirect functional connection between the second drive and the crosshead is also present, i.e.,

when the first drive is in idle as an intermediary of action,

when the first drive is in a static rest state as an acting intermediary,

when the first drive is in an active operating state as an intermediate of action, wherein in addition to the indirect drive force of the second drive, an additional, but not indirect, drive force of the first drive moves the crosshead, or

When, for example, the second drive is a ball screw drive, the second drive is arranged on the side of the support element facing away from the movable mold clamping plate, the second drive is in operative connection with the first drive via a spindle extending through the support element, and the first drive is in operative connection with the crosshead (see for this reason figure 1),

when, for example, the second drive is arranged on the side of the support element facing away from the movable mold clamping plate and is connected to the crosshead via a tie rod or the like extending through the support element, the first drive is arranged in or on the tie rod.

Further advantageous embodiments of the invention are defined in the dependent claims.

In a preferred embodiment, it can be provided that the first drive is a linear drive.

In a preferred embodiment, it can be provided that the first drive is a hydraulic drive, in particular a hydraulic linear drive, in particular a hydraulic cylinder with an accumulator and/or a hydraulic pump.

In a preferred embodiment, it can be provided that the first drive has a travel which is less than two-thirds of the travel of the second drive, in particular less than half the travel of the second drive, in particular less than one-third of the travel of the second drive.

In a preferred embodiment, it can be provided that the second drive is a linear drive.

In a preferred embodiment, it can be provided that the second drive is an electric drive, in particular a ball screw drive or a rack drive.

In a preferred embodiment, it can be provided that the second drive is in indirect operative connection with the crosshead of the toggle mechanism, wherein the first drive is in non-indirect operative connection with both the second drive and the crosshead of the toggle mechanism as an intermediate of the effect arranged between the second drive and the crosshead. In other words, the second driver is directly connected with the first driver, and the first driver is directly connected with the crosshead. In other words, in this embodiment, the second drive and the first drive are connected in series, both kinematically and geometrically, before the crosshead and thus cause a series movement sequence.

In a preferred embodiment, it can be provided that the toggle mechanism is a 5-point toggle lever.

In a preferred embodiment, it can be provided that at least one valve is provided for controlling or regulating at least one actuator and that the at least one valve is a rapidly switching seat valve.

In addition to the toggle closure unit itself, the invention also relates to a method for mold closure and mold opening and for building up and reducing the closing force of a toggle closure unit for a molding machine, in particular an injection molding machine, comprising:

at least one support element is provided for the support element,

a movable mold clamping plate which is arranged on the upper surface of the mold clamping plate,

a toggle mechanism, which is connected to the at least one support element and the movable mold clamping plate in an articulated manner,

-a fixed mold clamp plate, and

at least two drives, which are arranged in parallel,

wherein,

-the first driver is in operative connection with the crosshead of the toggle mechanism, and

said second drive being arranged between said first drive and said at least one support element,

the first drive has an energy store, in particular a hydraulic store, wherein the energy store provides energy for building up the closing force and/or stores energy when the closing force is reduced.

Drawings

Further advantages and details of the invention result from the drawing and the associated drawing description.

Here, in the drawings:

FIG. 1 shows an embodiment of a molding machine having a toggle closure unit according to the present invention;

FIG. 2 shows a graph of a preferred speed process and motion process;

FIG. 3 illustrates an embodiment of a hydraulic circuit diagram for controlling a first actuator;

fig. 4 shows an embodiment of a forming machine with a toggle closing unit according to the invention.

Detailed Description

Fig. 1 shows a molding machine. The two mold clamping plates each carry a molding mold, which is in a form-locking state. The fixed die clamping plate 5 is connected with the movable die clamping plate 3 through a beam. The movable mold clamp plate 3 is guided on the underside by guides which in turn rest on the machine base. The movable mold clamp plate 3 is part of the toggle closing unit 1 and can be moved by a toggle mechanism 4. The toggle closure unit 1 is composed of a support element 2, a movable mold clamp plate 4, a toggle mechanism 4 and two drives 6, 7. The toggle lever mechanism 4 is composed of a central cross head 8 and two eye levers, a middle lever and a tab.

The crosshead 8 can be moved along the machine longitudinal axis L by the first and second drives 6, 7. Thereby also moving the movable mold clamp plate 3 along the machine longitudinal axis L. In the depicted end position of the cross head 8, the toggle lever mechanism 4 is in its fully extended and locked position, whereby this results in a form-locking of the two forming tools and the closing force required for the forming process is already built up. If the crosshead 8 is again moved in the opposite direction along the machine longitudinal axis L, this results in a closing force reduction and a mold opening, wherein the movable mold clamp plate 3 is removed from the fixed mold clamp plate 5.

In this embodiment, the first driver 6 is a hydraulic cylinder. According to the invention, the first drive 6 is connected directly, i.e. not indirectly, to the cross head 8 and can move the same. Also according to the invention, a second driver 7 is arranged between the first driver 6 and the support element 2. In this embodiment, the second driver 7 is a ball screw driver. In this embodiment, the second drive 7 extends through the support element 2 and terminates directly in the hydraulic cylinder of the first drive 6. In this case, the second drive 7 and the first drive 6 are therefore likewise in non-indirect operative connection with one another. In other words, in this embodiment, the second drive and the first drive are connected in series both kinematically and geometrically before the crosshead and thus cause a series sequence of movements. The first driver 6 likewise extends through the support element 2. The hydraulic cylinder of the first drive 6 as a whole is in the support element 2. The hydraulic piston supported therein extends from the support element 2 until reaching the cross head 8.

The second drive 7 can be connected to the moving crosshead 8 via an indirect action. The interaction medium between the drive 7 and the crosshead 8 is either an idle or a locked first drive 6. For this purpose, the hydraulic piston of the first drive 6 is required to be moved either at idle until a stop or to its end position in the hydraulic cylinder, or the position of the hydraulic piston is locked by a locking hydraulic valve.

Fig. 2 shows a diagram of a preferred speed profile and a movement profile of the movable mold clamping plate 3. The speed v (with which the movable mold clamping plate 3 causes the path s) can be different. In this embodiment, the form-locking is shown by a quick travel E, which has a substantially trapezoidal course. During the closing force build-up, that is to say during the force travel K, different preferred speed profiles can be present.

Firstly, after the trapezoidal course of the rapid path E, the speed v can be zero for a short time, thus resulting in a short holding of the movable mold clamping plate 3. The movable mold clamp plate 3 then accelerates again and reaches a smaller speed v during the force stroke K than during the quick stroke E. Two speed processes E, K are shown in the diagram in a trapezoid and correspond to a continuous line profile.

In the second variant, it may be provided that no short-term holding of the movable mold clamping plate 3 is provided. The speed v of the movable die clamping plate 3 drops here as before during the trapezoidal course of the quick travel E, but the force travel K begins already with the second acceleration of the movable die clamping plate 3 before the speed v reaches zero at the end of the quick travel E. The force travel K can then reach a speed plateau as before. The two speed processes E, K are shown in a substantially trapezoidal form in the diagram and correspond to the solid line during the quick travel E and the long dashed line during the force travel K.

In the third and fourth course, instead of an at least substantially trapezoidal force course, the quick travel E may follow an at least substantially triangular course. In this case, the acceleration during the closing force build-up during the force path K is followed by a deceleration without a temporarily constant speed plateau being maintained. These decelerations are represented in the graph by the two short dashed lines during the force stroke K. As already mentioned, a rapid travel E with or without a short holding time (v=0) of the movable die clamping plate 3 can take place before the at least substantially triangular shape of the force travel K caused by the acceleration of the movable die clamping plate 3 and the subsequent deceleration.

The speed and movement processes shown here can be set in a preferred embodiment and do not have any limiting effect. Other undisclosed orientations are also possible.

Fig. 3 shows a cut-out of the molding machine together with two drives 6 and 7 and a hydraulic diagram for controlling the first drive 6. In this embodiment, the first driver 6 is a hydraulic cylinder, and the second driver 7 is a ball screw driver. The support element 2 is configured such that the spindle of the ball screw drive is supported therein. In this case, the spindle causes a translational movement along the longitudinal axis L of the machine by rotation of the spindle and its bearing in the support element 2. Since the spindle is directly connected to the hydraulic cylinder, which in turn is directly, i.e. indirectly, connected to the crosshead 8, the ball screw drive is able to drive the crosshead 8 whether the hydraulic cylinder also acts as a drive or as an intermediate of action. In this way, the hydraulic cylinder as the first drive 6 and the ball screw drive as the second drive 7 can move the cross head 8 along the machine longitudinal axis L either together or separately.

If the first drive 6 is a hydraulic cylinder as in this embodiment, it can be controlled or regulated by means of a hydraulic map. The hydraulic system required for this purpose may consist of a hydraulic accumulator 9, a hydraulic pump 10, various valves 11 and hydraulic pistons as hydraulic drives 6 in pipes, containers, for example hydraulic storage tanks and hydraulic cylinders. The hydraulic accumulator 9 is an accumulator which can store and release energy as a hydraulic spring. In this embodiment, the hydraulic accumulator may provide pressure to build up the closing force and store energy in the form of pressure when the closing force is relieved. The hydraulic pump 10 pumps a hydraulic medium, typically hydraulic oil, through a hydraulic line system. The valve shown in this embodiment may be an electrically regulated shut-off valve.

When the hydraulic pump 10 delivers oil from the reservoir into the pipe system, the oil can be pumped into the hydraulic reservoir 9, the left or right chamber of the hydraulic cylinder 6 by switching the valves 11 accordingly. This can increase the energy of the hydraulic accumulator 9. In other words, the hydraulic spring can be acted upon thereby. On the other hand, the hydraulic cylinder 6 can be operated by a hydraulic pump 10. If pumped into the left chamber of the hydraulic cylinder 6, the piston follows a movement to the right due to the pressure and thus presses the crosshead 8 to the right along the machine longitudinal axis L, which corresponds to the movement of the closing force build-up. At the same time, it is necessary that hydraulic oil can escape from the right chamber of the hydraulic cylinder 6 and flow out into the reservoir via a hydraulic line system with a correspondingly open valve 11. Conversely, if pumped into the right chamber of the hydraulic cylinder, the piston follows a leftward movement due to the pressure and thus presses the crosshead 8 to the left along the machine longitudinal axis L, which corresponds to a movement that reduces the closing force. At the same time, it is necessary that hydraulic oil can escape from the left chamber of the hydraulic cylinder 6 and flow out into the reservoir via a hydraulic line system with a correspondingly open valve 11. The valves required for this are shown in solid lines in fig. 3.

In the sense of recovery, a portion of the energy required for closure force build-up can be recovered from the process cycle by: the additional valve 11 shown in dashed lines in fig. 3 is actuated accordingly. If, for example, the closing force of the mold clamping plate and its molding tool or the hydraulic pressure of the hydraulic cylinder 6 present thereby is released after molding, a part of this pressure can be absorbed by the hydraulic system in the hydraulic accumulator 9 in order to again supply this recovered energy for the closing force build-up of the next molding cycle.

Fig. 4 shows an embodiment of a forming machine with a toggle closing unit 1 according to the invention. Two mold clamping plates 3 and 5, a toggle mechanism 4 and a support element 2 can be seen. The crosshead 8 of the toggle mechanism 4 is connected non-indirectly to the two first drives 6. In this example, the first driver 6 is a hydraulic cylinder. The first drivers 6 are connected in parallel. The first drivers are respectively at the ends of the tie rod 14. The two tie rods 14 extend through the support element 2 from the side facing the movable die clamping plate to the side facing away from the movable die clamping plate. Two tie rods 14 are connected to the bracket 12 at respective other ends. The spindle of the second driver 7 passes through the bracket 12. In this embodiment there is only one second driver 7. In this embodiment, the one second driver 7 is a ball screw driver.

By means of a nut 13, which is located on the spindle of the one second drive 7 and is connected to the support 12, it is possible to manipulate, in particular move the support 12, kinematically then the tie rod 14 extending through the support element 2, kinematically then the two first drives 6 and kinematically then the crosshead 8 by means of the spindle of the rotation of the second drive 7.

In this case, an indirect operative connection exists between the second drive 7 and the crosshead 8. In this embodiment, the action between the second driver 7 and the crosshead 8 is mediated in a kinematic sequence starting from the movement of the second driver 7: nut 13, bracket 12, two tie rods 14 and two first drivers 6.

When the two first drives 6 are switched on in idle mode, an indirect operative connection is also present between the second drive 7 and the cross head 8. In this case, the second drive has to move the action intermediate in front of the two first drives 6 up to the stop of the hydraulic piston in order to be able to move the cross head 8 next.

When the two first drives 6 are in a stationary, stationary state, an indirect operative connection is also present between the one second drive 7 and the cross head 8. When the same hydraulic pressure is constantly present in both pressure chambers of the hydraulic cylinder and thus the hydraulic piston does not move relative to the hydraulic cylinder, the hydraulic pistons of the two first drives 6 are in a static, stationary state. In this case there is no lost motion and the one second drive 7 can move the crosshead through the above-mentioned action intermediary.

When both first drives 6 are in the active operating state, an indirect operative connection is also present between the one second drive 7 and the cross head 8. In this case, both first drives 6 fulfil the function of an interaction agent not only during the indirect interaction connection between the one second drive 7 and the cross-head 8, but also the additional function of a drive in non-indirect interaction connection with the cross-head 8. That is, in addition to the indirect driving force of the second driver 7, the additional non-indirect driving force of the first driver 6 moves the crosshead 8.

In this embodiment with two first drives 6 and one second drive 7 capable of moving the crosshead 8, any desired distribution of the driving force is possible. For example, the two first drives 6 can be connected with different intensities in order to balance the tilting moment.

The invention is not limited to the number of drives shown nor to their location in a molding machine, in particular an injection molding machine.

List of reference numerals

1. Toggle rod closing unit

2. Support element

3. Movable die clamping plate

4. Toggle rod mechanism

5. Fixed die clamping plate

6. First driver

7. Second driver

8. Crosshead

9. Energy accumulator

10. Hydraulic pump

11. Valve

12. Support frame

13. Nut

14. Pull rod

15. Sealing part

Longitudinal axis of L machine

E quick travel, corresponding to mold opening or mold closing

K force travel, build-up or reduction corresponding to closing force

v speed

s distance of movable die clamping plate 3

Claims (10)

1. Toggle closure unit (1) for a molding machine, in particular an injection molding machine, comprising:

-at least one support element (2);

-a movable mold clamp plate (3);

-a toggle mechanism (4) hinged to said at least one support element (2) and to said movable mould clamp plate (3);

-a fixed mould clamping plate (5); and

-at least two drives (6, 7);

wherein,

-the first drive (6) is in non-indirect operative connection with the crosshead (8) of the toggle mechanism (4); and

a second drive (7) is arranged kinematically between the first drive (6) and the at least one support element (2),

the first drive (6) has an energy store (9), in particular a hydraulic store, wherein the energy store (9) provides energy for building up the closing force and/or stores energy when the closing force is reduced.

2. Toggle closing unit according to claim 1, characterized in that the first actuator (6) is a linear actuator.

3. Toggle closing unit according to at least one of the preceding claims, characterized in that the first drive (6) is a hydraulic drive, in particular a hydraulic linear drive, in particular a hydraulic cylinder with an accumulator (9) and/or a hydraulic pump (10).

4. Toggle closing unit according to at least one of the preceding claims, characterized in that the first actuator (6) has a stroke with a length of less than two thirds of the stroke of the second actuator (7), in particular less than half the stroke of the second actuator, in particular less than one third of the stroke of the second actuator.

5. Toggle closing unit according to at least one of the preceding claims, characterized in that the second drive (7) is a linear drive.

6. Toggle closure unit according to at least one of the preceding claims, characterized in that the second drive (7) is an electric drive, in particular a ball screw drive or a rack drive.

7. Toggle closing unit according to at least one of the preceding claims, characterized in that the second drive (7) is in indirect operative connection with the crosshead (8) of the toggle mechanism (4), wherein the first drive (6) is in non-indirect operative connection with not only the second drive (7) but also with the crosshead (8) of the toggle mechanism (4) as an operative intermediary arranged between the second drive and the crosshead.

8. Toggle closing unit according to at least one of the preceding claims, characterized in that the toggle mechanism (4) is a 5-point toggle.

9. Toggle closing unit according to at least one of the preceding claims, characterized in that at least one valve (11) is provided for controlling or regulating at least one actuator (6, 7), and that the at least one valve (11) is a fast switching seat valve.

10. Method for mold closing and mold opening, for building and subtracting a closing force of a toggle closing unit (1) for a molding machine, in particular an injection molding machine, comprising:

-at least one support element (2);

-a movable mold clamp plate (3);

-a toggle mechanism (4) hinged to said at least one support element (2) and to said movable mold clamp plate (3),

-a fixed mould clamping plate (5); and

-at least two drives (6, 7);

wherein,

-the first drive (6) is in operative connection with the crosshead (8) of the toggle mechanism (4); and

a second drive (7) is arranged kinematically between the first drive (6) and the at least one support element (2),

the first drive (6) has an energy store (9), in particular a hydraulic store, wherein the energy store (9) provides energy for building up the closing force and/or stores energy when the closing force is reduced.