EP3998218A1 - Work station with lifting mechanism for a packaging machine - Google Patents

Abstract

The invention relates to a work station, in particular a deep-drawing station, forming station, sealing station, cutting station or punching station, for a packaging machine, with a frame supported on the floor, a working unit comprising an upper part and a lower part, and a lifting mechanism carried by the frame, with which the lower part of the The working unit can be raised and lowered relative to the frame to carry out a lower lift, the lifting mechanism having a drive which has at least one shaft (17) extending in the transverse direction, a drive motor acting on the shaft for rotating the shaft and at least one drive motor on the input side with the Shaft-coupled transmission (23, 25, 61, 71), on which the lower part is supported on the output side and which converts a rotation of the shaft into the lower stroke of the lower part. The upper part can be lowered and raised relative to the frame to perform an upper lift. The shaft is mounted eccentrically on the frame with respect to its axis of rotation.

Description

The invention relates to a work station, in particular a deep-drawing station, forming station, sealing station, cutting station or punching station, for a packaging machine, with a frame supported on the floor, a working unit comprising an upper part and a lower part, and a lifting mechanism carried by the frame, with which the lower part the working unit can be raised and lowered relative to the frame for performing a lower lift, the lifting mechanism having a drive which has at least one shaft extending in the transverse direction, a drive motor which acts on the shaft for rotating the shaft and at least one drive motor which is coupled to the shaft on the input side Transmission includes, on the output side, the base is supported and converts a rotation of the shaft in the lower stroke of the base.

Such work stations are known in principle and are used in particular on packaging machines on which the packaging is produced from webs of film. First, indentations are produced in a lower film in a deep-drawing or forming process, then objects to be packaged, such as food products, are placed in the indentations, the indentations are then sealed with an upper film, and the individual packs are then separated by cutting or punching out.

At least at some work stations of the packaging machine, it is necessary to raise and lower the tools used for the respective work process. A deep-drawing station, for example, has a working chamber formed from an upper chamber part and a lower chamber part which, in the open state, the film web can be conveyed through and in which, in the closed state, the mentioned depressions are produced by the film web being subjected to negative pressure from the lower chamber and compressed air via the upper chamber. To close the chamber, the two chamber parts must be pressed together. In addition, high additional forces act on the chamber parts during the deep-drawing process due to the pressure being applied to a relatively large area. Consequently, the lifting mechanism provided for opening and closing the chamber, the frame carrying the lifting mechanism and the devices for supporting the lifting mechanism on the frame are in practice exposed to considerable loads which can correspond to a weight of several tons.

Known work stations for packaging machines are therefore designed to be correspondingly massive and are provided with correspondingly powerful, large motor drives and lifting mechanisms for performing the lifting movement. Such workstations are therefore large, heavy and expensive. Furthermore, some of these workstations are only specially designed for an assigned tool or pack format, so that there is a constant maintenance effort depending on the structure and use of components.

In addition, it is necessary in practice at some workstations not only to raise and lower the lower part of the respective work unit, but also to carry out a so-called upper lift in addition to this lower lift, ie also to raise and lower the upper part of the work unit. At a deep-drawing station, for example, it should be ensured that the heating devices integrated in the upper chamber for heating the film web do not act on the film web too early before the actual deep-drawing process, but rather the effect of heat only begins when the chamber is closed or at the start of the closing process. The top lift function leads to an even more complex structure of the known work stations. In particular, additional drives are required for this deployed. However, even without an upper lift functionality, some known work stations already have a large number of movable elements for executing the lower lift, as well as a plurality of drives which have to be synchronized in a complex manner.

Well-known workstations for packaging machines are, for example, in EP 1 118 540 B1 , DE 103 51 567 B4 , DE 10 2004 006 118 A1 , DE 10 2008 019 626 A1 , DE 10 2015 211 622 A1 and EP 2 666 727 B1 described.

The object of the invention is to provide a workstation of the type mentioned at the outset which, with a simple and space-saving design, has an efficient and highly resilient lifting mechanism.

This problem is solved in each case by the independent claims.

According to an independent aspect of the invention it is provided that the shaft of the lifting mechanism is supported on the frame and carries a base on which the upper part is supported.

This concept makes it possible in an advantageous manner to absorb the forces occurring during the work process, for example when closing the chamber of a deep-drawing station, within the lifting mechanism without influencing the frame. The support of the lifting mechanism on the frame therefore only needs to introduce the weight of the lifting mechanism into the frame, but not the process forces acting within the lifting mechanism when executing the lower lift and during the raised lower part, i.e. in a deep-drawing station with the working chamber closed.

Based on a possible practical embodiment, this means, for example, that the lifting mechanism is supported on the frame only for a weight force must be designed to weigh a few 100 kg, whereas process forces are effective within the lifting mechanism that correspond to a weight of more than 10 t.

According to the invention, the lifting mechanism consequently forms a mechanically independent and self-contained unit in terms of function and in terms of the process forces effective during operation, which only needs to be carried by the frame of the workstation.

Advantageous refinements, which can also be provided in connection with the further independent aspects of the invention explained elsewhere, are specified below and also result from the claims and the figures as well as the associated description of the figures. This also applies in each case to the further independent aspects of the invention.

The base carried by the shaft supported on the frame may include a frame. Such a frame, which has, for example, a rectangular box structure with two longitudinal members and two transverse members, can ensure particularly high stability of the lifting mechanism. The interior of this stability frame is available in particular for moving parts of the lifting mechanism.

The gear provided between the shaft and the lower part is preferably designed as a coupling gear, in particular as a sliding crank gear. It is preferably a centric slider-crank mechanism.

The transmission between shaft and base can include a toggle lever arrangement. In particular, the toggle lever arrangement is stretched in a position with the lower part raised to the maximum, which corresponds in particular to a closed working unit. This can ensure that at maximum No torque is exerted on the shaft by the process forces from the lower part. This position of the transmission is also referred to below as the extended position or as the neutral position.

The transmission between the shaft and the lower part can comprise at least one pair of congruent and spaced-apart connecting rods, between which a shaft crank rotatably connected to the shaft is articulated on the input side and the lower part or a carrier for the lower part is articulated on the output side.

Such a symmetrical structure prevents the occurrence of disruptive tilting moments. Measures for absorbing or storing or dissipating corresponding lateral forces can thus be omitted.

Preferably, the shaft is journaled for rotation in transversely spaced longitudinal members of the base. As a result, the shaft can carry the base in a particularly simple structural manner and also increase the stability of the base due to the cross connection formed by the shaft between the longitudinal members.

The gear mechanism preferably comprises at least two individual gear mechanisms which are spaced apart along the shaft and are synchronized by means of the shaft, for joint execution of the lower stroke. Consequently, a shaft can act on the base at a plurality of transversely spaced locations, each via a gear. This further increases the stability and ensures a distribution of the process forces that are effective during operation.

The lifting mechanism preferably comprises a plurality of shafts which are spaced apart and synchronized along the frame and each have a gear for jointly executing the lower lift. In turn, multiple shafts increase the stability of the lifting mechanism, since they are at longitudinally spaced locations on the base can be attacked. In principle, any number of shafts can be selected, in particular in order to adapt the lifting mechanism to the required overall length of the workstation.

Several shafts are particularly advantageous in combination with the embodiment explained above, according to which the gear in question is divided into at least two individual gears spaced apart along the shaft on each shaft.

Preferably, two synchronized individual gears are provided per shaft, which are arranged in the area of the outer sides of the lifting mechanism, i.e. each shaft engages on the lower part with a left-hand individual gear and a right-hand individual gear - e.g. seen in the conveying direction of a film web running through the work station. The space between the two individual gears can then be used for other purposes.

A particularly precise sequence of movements of the lower part relative to the upper part can be achieved in that, according to a further embodiment, the lower part is guided during the lower stroke on the base, on the upper part or on a column supporting the upper part on the base. To further increase the stability of the lifting mechanism, it can be provided that the column stands directly above the shaft, i.e. the column is supported on the base in such a way that a vertical central axis of the column intersects the axis of rotation of the shaft.

According to a preferred structure of the transmission explained above, a left and a right column can be provided for a respective shaft, so that the upper part in the region of this shaft is supported at two transversely spaced points on the base and thus on the shaft carrying the base.

The arrangement of the columns directly above the shafts advantageously ensures that the weight of the upper part is diverted directly into the shaft and thus into the frame.

The upper part can be supported on the base so that it can be adjusted in height. This allows the position of the upper part to be adjusted, for example, relative to a film plane, i.e. to the plane that is defined by a film web running through the work station and is therefore external, i.e. not determined by the work station but by the packaging machine in which the work station is integrated.

Several columns supporting the upper part on the base can simultaneously serve to adjust the position of the upper part if, according to a further exemplary embodiment of the invention, the columns or their supports on the base are designed to be adjustable in height.

According to a further exemplary embodiment, the drive motor acts on the shaft via a linkage. This coupling gear is not to be understood as meaning the motor gear having the drive shaft of the motor as the input member, but a coupling gear which comprises an output member, for example a motor crank, which can be set in rotation by means of the drive motor and interacts with the shaft via the coupling gear.

In a preferred embodiment of the invention it is provided that in a position with the lower part maximally lowered, which corresponds in particular to an open working unit, the torque applied via the linkage to a drive shaft of the drive motor is zero or approximately zero. As a result, the drive motor does not need to apply any holding torque when the lower part is lowered to the maximum, so that, for example, the drive motor can be replaced without any problems in this situation.

In a preferred embodiment, the linkage is designed as a four-bar linkage, which comprises a drive shaft of the drive motor, a motor crank connected to the drive shaft, a drive coupling connected in an articulated manner to the motor crank, and a shaft crank connected in a rotationally fixed manner to the shaft and in an articulated manner to the drive coupling. In particular, a motor gear is provided between the drive shaft of the motor and the motor crank, which will not be discussed in detail at this point.

The arrangement of such a four-bar linkage between the drive motor and the shaft enables, in particular, an advantageous interaction with the transmission between the shaft and the lower part if the two transmissions are matched to one another. This is dealt with in more detail elsewhere.

In a preferred embodiment of the invention, it is provided that in a position with the lower part lowered to the maximum, which corresponds in particular to an open working unit, the axis of rotation of the drive shaft of the drive motor, the axis of articulation between the motor crank and the drive coupling and the axis of articulation between the drive coupling and the shaft crank are at least approximately in one plane lie. This position of the linkage is also referred to below as the extended position or as the neutral position. An advantage of this position is that no torque acting in the sense of a further lowering of the lower part can be applied to the drive shaft of the motor via the shaft, which means the above-mentioned possibility of easy replacement of the motor.

The drive motor is preferably an electric motor, in particular a servo motor. Alternatively, a pneumatic or hydraulic drive can also be provided.

According to a further embodiment of the invention, the base can be lowered and raised relative to the frame in order to carry out an upper lift of the upper part. This allows the lifting mechanism to be provided with an integrated top lift function. Possible configurations of the lifting mechanism for realizing this upper lift function will be discussed in more detail elsewhere.

The lower lift and the upper lift are preferably positively coupled to one another. As a result, the lower stroke movement and the upper stroke movement can support each other in an advantageous manner. This forced coupling preferably takes place through the shaft.

It is preferably provided that the lower stroke and the upper stroke run in opposite directions to one another.

Furthermore, according to one embodiment of the invention, it is provided that the lifting mechanism can be adjusted in the longitudinal direction relative to the frame. As a result, the workstation can be adapted in the simplest way possible to different applications in the operation of the packaging machine, in particular to different format sets, i.e. arrangements of a predetermined number of packages relative to one another, or to the timing of the packaging machine.

An adjustability of the lifting mechanism as a whole relative to the frame results in particular from the fact that the lifting mechanism is a self-contained unit that is only supported on the frame via one or more shafts. This makes it possible, according to a preferred embodiment of the invention, to form the lifting mechanism in the manner of a carriage or carriage, which can be moved or moved as a whole on the frame in order to to be brought into the desired position within the work station and consequently within the respective packaging machine.

In particular, it can be provided that the lifting mechanism is supported on the frame via a plurality of support elements, in particular rollers or shafts, and can be adjusted, in particular moved, in the longitudinal direction relative to the frame by means of the support elements.

The frame can have at least two parallel, spaced-apart carrier profiles running in the longitudinal direction, on which the lifting mechanism is supported and along which the lifting mechanism can be adjusted relative to the frame.

In particular, the lifting mechanism and the frame can interact as a wheel/rail system with regard to adjustability in the longitudinal direction. For lateral guidance of the lifting mechanism on the frame, the support members, which are preferably designed as rollers, can each be provided with a notch or a step.

According to a further exemplary embodiment, a fixing device can be provided, by means of which the position of the lifting mechanism can be fixed in the longitudinal direction on the frame. The fixing device can include a spindle drive for adjusting the longitudinal position of the lifting mechanism. The spindle drive can comprise a spindle attached to the frame and a spindle nut, the spindle nut preventing a movement of the lifting mechanism relative to the frame in the longitudinal direction and allowing it in the lifting direction.

The spindle nut can, for example, be connected in a longitudinally displaceable manner to a column supporting the upper part on the base, in order in this way to enable an upper lifting movement of the upper part.

According to a further independent aspect of the invention, the lifting mechanism comprises a plurality of shafts which are spaced apart along the frame and are synchronized, each with a gearbox for jointly carrying out the lower lift.

By providing a plurality of shafts, the lifting mechanism can act on the lower part at longitudinally spaced points. This increases stability and ensures precise alignment of the bottom relative to the top.

Precisely one drive motor is preferably provided for the synchronous rotation of the shafts. This simplifies the construction of the elevating mechanism and reduces the cost.

The drive motor is preferably located longitudinally outside of each pair of shafts. This has the advantage that the drive motor does not get in the way of the moving parts of the lifting mechanism. The space between the shafts can consequently be used for other purposes.

The drive motor or an axis of rotation of a drive shaft of the drive motor preferably lies at least approximately in a plane defined by the axes of rotation of the shafts. Installation space above or below this level defined by the shafts is therefore not required for the drive motor.

According to a further exemplary embodiment, it is provided that the shafts are supported on the frame and together carry a base, preferably comprising a frame, on which the upper part is supported, with the drive motor being arranged outside the base. By arranging the drive motor outside the base, the inside of the base is otherwise available, for example for electrical, pneumatic or hydraulic lines in connection with the function of the tool used in the work station. In particular, when designing the moving parts of the The lifting mechanism and its kinematics are not taken into account by the drive motor itself.

Preferably, the drive motor is supported on a cross member of the base.

Furthermore, it is preferably provided that the drive motor is arranged in such a way that a drive shaft of the drive motor runs parallel to the shafts. This facilitates the coupling between the drive motor and the shaft. In particular, an angular gear for the drive motor can be dispensed with.

Preferably, the shafts are mechanically synchronized.

The shafts can preferably be rotated in the same direction. This enables a particularly simple structure and a space-saving arrangement of the moving parts for synchronous rotation of the shafts.

According to an exemplary embodiment of the invention, the shafts are connected to one another by at least one synchronization coupler. It is provided in particular that the drive motor acts on one of the shafts via a linkage and on the or each other shaft via the synchronization coupling coupled to the linkage. If more than two shafts are provided, either a single synchronization coupler connecting all shafts can be provided. Alternatively, several synchronization couplings connected in series can be provided. This has the advantage that the synchronization couplers can act on the shafts at different transverse positions. As a result, the structure of the lifting mechanism can be made more flexible.

According to a further embodiment, it is provided that the synchronization coupler acts on the shafts in each case via a shaft crank which is non-rotatably connected to the shaft.

According to a further independent aspect of the invention, it is provided that the drive motor acts on the shaft via a gear.

As already mentioned above, by providing a gear between the drive motor and the shaft, this gear can be matched to the gear between the shaft and the lower part with regard to the respective circumstances. This applies not only to the situations explained in more detail below when the lower part is raised to the maximum and the lower part is lowered to the maximum, but also the sequence of movements and the course of the forces or torques during the execution of the lifting movement between the two extreme positions mentioned.

In particular, the structure of the gears and the arrangement of the moving parts within the lifting mechanism and thus within the work station on the one hand and the torque curve on the other hand can be coordinated in such a way that a relatively small drive motor with comparatively low power is sufficient to carry out the lifting movement required in each case, and the moving parts of the lifting mechanism require little space.

With regard to possible configurations of the gear provided between the drive motor and the shaft, reference is made to the above statements.

In a preferred embodiment, it is provided that the transmission between the lower part and the shaft and the transmission between the drive motor and the shaft are designed and coordinated in such a way that when the maximum lifted Lower part and at the maximum lowered lower part each one of the transmission occupies a neutral position.

In particular, when the lower part is raised to the maximum, the torque applied by the lower part to the shaft is zero or approximately zero. This can be achieved, for example, by a toggle lever arrangement of the transmission between the shaft and the lower part that is stretched in this position.

Furthermore, it can be provided in particular that when the lower part is lowered to the maximum, the torque applied by the lower part to a drive shaft of the drive motor is zero or approximately zero. As already mentioned elsewhere, this can be achieved, for example, by a stretched configuration of a four-bar linkage that forms the transmission between the drive motor and the shaft.

As a common element and in particular as the only common element of the two gears, a shaft crank non-rotatably connected to the shaft can be provided.

Furthermore, a preferred embodiment provides that a motor crank connected to the drive motor rotates through a larger angle than the shaft when the maximum lifting path of the lower part is executed. In particular, the angle of rotation of the motor crank can be greater by about 20 to 70%, in particular by about 40 to 60%, than the angle of rotation of the shaft.

In a practical embodiment, the maximum stroke of the lower part corresponds to a rotation of the shaft by approximately 80° to 120°, in particular by approximately 100°.

Furthermore, it can be provided that the maximum lifting distance of the lower part corresponds to a rotation of a motor crank connected to the drive motor by approximately 140° to 160°, in particular by approximately 150°.

According to a further independent aspect of the invention, it is provided that the upper part can be lowered and raised relative to the frame in order to carry out an upper lift.

As already mentioned, some applications require that not only the lower part of the working unit can perform a lower lift, but also the upper part can be lowered and raised relative to the frame.

A particularly advantageous possibility for performing an upper lift results from a construction of the lifting mechanism and a way of supporting the lifting mechanism on the frame, as explained above in connection with one of the other independent aspects of the invention. The possibility of performing an upper lift is not mandatory with such a concept, but can be implemented in a simple manner in order to integrate an upper lift function into the lifting mechanism.

Accordingly, the upper part is preferably supported on the frame via the lifting mechanism. In particular, the upper part is supported on the frame via the shaft.

A preferred way of integrating an upper lift function into the lifting mechanism provides that the shaft is eccentrically mounted on the frame with respect to its axis of rotation. A rotation of the shaft about its axis of rotation consequently results in a movement of the axis of rotation relative to the frame with a vertical component. This movement of the shaft can be used to perform a top lift movement of the upper part.

Consequently, according to the invention, a lifting mechanism with a centrally mounted shaft and without an upper lift function can easily be converted into a lifting mechanism with an upper lift function by changing the central mounting of the shaft to an eccentric mounting. In addition, by changing the eccentricity of the eccentric bearing of the shaft, the relationship between the angle of rotation of the shaft and the stroke distance of the upper stroke movement resulting therefrom can be changed.

The upper part is preferably supported on a base of the lifting mechanism, preferably comprising a frame, with the shaft being rotatably mounted in the base.

If the shaft is mounted and rotated eccentrically with respect to its axis of rotation, the resulting vertical movement of the shaft is transferred to the base and thus to the upper part.

To support the shaft on the frame, at least two support members can be provided which are spaced apart along the shaft and on which the shaft is mounted eccentrically with respect to its longitudinal axis. Consequently, when the shaft rotates, the shaft moves in a vertical direction relative to the support members, in order in this way to carry out the upper lift function.

So that the shaft can be fixed relative to the frame during its rotation in the longitudinal direction, it can be provided according to a further preferred embodiment that the support members are capable of an evasive movement in the longitudinal direction. In this way, the horizontal component resulting from the rotation of the eccentrically mounted shaft can be recorded.

Preferably, the supporting members each comprise a roller or cylinder.

In this way, while a rotation of the shaft not only causes the lower part to be raised and lowered, but also results in a vertical movement of the shaft, which can be translated into an upward or downward movement of the upper part, this means that the lower stroke of the lower part and the upper stroke of the upper part are positively coupled to each other via a rotation of the shaft.

Provision is preferably made for the lower stroke and the upper stroke to run in opposite directions to one another. The two lifting movements can consequently support each other, as a result of which the maximum power to be applied by the drive motor can be significantly reduced.

In a possible practical embodiment, the effective working stroke of the working unit, given by the difference between the lower stroke and the upper stroke, is approximately 75 to 85 mm, preferably approximately 80 mm.

Preferably, the maximum amount of upstroke is about 0.2 to 0.3 times the maximum amount of downstroke.

The maximum amount of the upper stroke is preferably around 20 to 30 mm, preferably around 25 mm.

In particular, it can be provided that the maximum amount of the understroke is approximately 95 to 115 mm, preferably approximately 105 mm.

These configurations can each be combined with the above-mentioned practical configurations relating to the possible angles of rotation of the shaft (in particular about 100°) and the motor crank (in particular about 150°). the maximum stroke of the lower part, ie for the maximum lower stroke, be provided.

The invention also relates to a packaging machine with at least one work station according to the invention.

Fig. 1

eine perspektivische Ansicht einer Arbeitsstation mit einem Hubmechanismus gemäß einer ersten Ausführungsform der Erfindung,

Fig. 2 und 3

unterschiedliche Seitenansichten des erfindungsgemäßen Hubmechanismus von Fig. 1, und

Fig. 4 bis 6

verschiedene Ansichten eines Hubmechanismus gemäß einer zweiten Ausführungsform der Erfindung.

The invention is described below by way of example with reference to the drawing. Show it:

1

a perspective view of a workstation with a lifting mechanism according to a first embodiment of the invention,

Figures 2 and 3

different side views of the lifting mechanism according to the invention from 1 , and

Figures 4 to 6

different views of a lifting mechanism according to a second embodiment of the invention.

At the in 1 The work station shown is a deep-drawing station of a packaging machine, which comprises a floor-standing frame 11 with two upper support profiles 51 and two lower support profiles 37, which extend in a conveying direction, also referred to below as the longitudinal direction, in which a film web (not shown). in a basically known manner by the packaging machine and thus by the in 1 shown thermoforming station is conveyed through. Towards the inside, chain guides (not shown) are attached to the support profiles 51 for guiding conveyor chains, also not shown, which laterally hold the film web running through in a basically known manner.

In the 1 The film plane 55 indicated by dashed lines, in which the film conveyor device (not shown) and the film web lie during operation, represents the reference plane for the tool of the deep-drawing station shown. In practice, this reference plane is usually slightly below the upper edge of the support profile 51 The tool is a working chamber, also referred to as a deep-drawing chamber, which comprises a lower part 15 and an upper part 13 . The height of this reference plane above the floor on which the frame 11 of the deep-drawing station and the packaging machine stand is specified by the packaging machine, so that the movements of the lower part 15 and the upper part 13 of the working chamber of the deep-drawing station must be coordinated with the position of the film plane 55 .

The lower part 15 and the upper part 13 are carried by a lifting mechanism, explained in more detail below, which is used as an independent functional unit in the work station between the two lower support profiles 37 and the two upper support profiles 51 . The lifting mechanism is carried as a whole by the frame 11 and is supported for this purpose exclusively by means of support members in the form of rollers 35 on the carrier profiles 37.

The two upper support profiles 51 and the two lower support profiles 37, on which the lifting mechanism is supported via the rollers 35, are attached to the outer sides of two longitudinally spaced, plate-like transverse elements 53, which are supported with feet 57 on the ground. The lifting mechanism is consequently located within a frame formed by the frame 11 as a supporting structure, which includes the two transverse elements 53, the two upper support profiles 51 and the two lower support profiles 37.

The following based on 1 regarding its basic structure explained lifting mechanism is then in connection with Figures 2 to 6 described in more detail.

The basic structure of the lifting mechanism comprises at the bottom a box-shaped frame made up of two lateral, longitudinally extending longitudinal beams 20 which are connected to one another by two crossbeams 22 . This frame forms a stable base for the lifting mechanism.

Several - in the embodiment 1 three - shafts 17 are rotatably mounted in the region of their ends in the longitudinal beams 20 of the frame. The support rollers 35 already mentioned are connected to the end faces of the shafts 17 and are therefore not directly connected to the longitudinal beams 20 of the frame.

The support of the lifting mechanism on the frame 11 is therefore characterized in that the shafts 17 are supported on the one hand via the rollers 35 on the carrier profiles 37 of the frame 11, and on the other hand the shafts 17 support the longitudinal beams 20 and thus the frame and consequently the entire lifting mechanism wear.

The frame comprising the longitudinal beams 20 and the transverse beams 22 forms a base of the lifting mechanism, on which the upper part 13 of the working chamber is directly supported. For this purpose, columns 27 are provided which are each supported vertically above one of the shafts 17 on the longitudinal beams 20 and carry a respective longitudinal element 59 of the upper part 13 .

A manually operable height adjustment is provided between the lower end of each column 27 and the respective longitudinal beam 20 of the frame, which enables the distance between the upper part 13 and the frame to be adjusted so that the position of the upper part 13 in relation to the position of the lower part 15 in the closed State can be set exactly and in particular the film thickness is taken into account.

Due to the fact that the lifting mechanism is supported on the frame 11 via the rollers 35, the lifting mechanism is a carriage which can be moved in the longitudinal direction relative to the frame 11 when the packaging machine is being set up. The lifting mechanism is not completely freely movable, but is coupled to the frame 11 via a fixing device in the form of a spindle drive comprising a spindle 39 and a spindle nut 41 . The spindle 39 extends longitudinally and is mounted on the frame 11 in such a way that it can be rotated about its longitudinal axis by manual operation. By rotating the spindle 39, the spindle nut 41 connected to the column 27 is acted upon in the longitudinal direction and the lifting mechanism is thereby moved in the longitudinal direction. The longitudinal position of the lifting mechanism in the frame 11 can consequently be changed and adapted to a particular application, but the longitudinal position of the lifting mechanism is fixed by the fixing device formed by the spindle drive 39, 41 during the deep-drawing operation.

To perform an upper lift, which will be explained in more detail below, the lifting mechanism as a whole can be raised and lowered. This means that the frame 20, 22 together with the upper part 13 supported by the columns 27 and the lower part 17 carried by the shafts 17 can be raised and lowered relative to the frame 11. In order to make this upper stroke possible, the spindle nut 41 is mounted on the relevant column 27 so that it can be displaced longitudinally.

The lower part 15 is supported on the shafts 17 via a transmission described in more detail below, from which FIG 1 a pair of congruent and spaced-apart push rods 23 is shown, between which a carrier 16 of the lower part 15 is articulated.

The shafts 17 are connected by an in 1 not shown common synchronization coupling 43 connected to each other and thereby mechanically synchronized. Actuation of the synchronization coupler 43 to synchronously rotate the shafts 17 is effected by a drive motor 19 arranged outside the frame 20, 22 at the level of the shafts 17. The motor 19 is on the in 1 rear cross member 22 of the frame and installed transversely insofar as the in 1 non-illustrated drive shaft of the motor 19 extends parallel to the shafts 17.

On the outer sides of the two supports 16 of the lower part 15, an outwardly protruding tab 61 is fastened, which is guided along one of the columns 27 supporting the upper part 13 on the longitudinal member 20 of the frame. As a result, the lower part 15 is guided on the upper part 13 when a lower stroke is carried out. In this way, the lower part 15 and the upper part 13 are precisely aligned relative to one another.

the Figures 2 to 6 show a first embodiment ( 2 and 3 ) and a second embodiment ( 4 , 5 and 6 ) of a lifting mechanism according to the invention. The lifting mechanism according to 2 and 3 corresponds to the lifting mechanism of the in 1 illustrated workstation. The lifting mechanism according to 4 , 5 and 6 is basically as per the lifting mechanism 2 and 3 constructed, but has a smaller working length provided for smaller tools and is provided with only two shafts 17 for this purpose, whereas the lifting mechanism according to FIG 2 and 3 has three shafts 17 arranged one behind the other in the longitudinal direction.

In some representations, some components are not shown in order to clarify special features of the structure. For example, in Figure 2a in the case of the left gear, the roller 35 and the connecting rod 23 at the front in this side view are not shown. In Figure 2b for example, the rollers 35 and the front push rods 23 are not shown in any of the three transmissions. On the other hand is in Figure 2b the motor shaft 29 to recognize. This applies accordingly to the Figures 3a and 3b . In addition, the Figure 2a and 3a each have a front carrier profile 37, whereas in the Figure 2b and 3b a rear support profile 37 of the frame is shown in each case. In the 4 , 5 and 6 the lifting mechanism is shown without components belonging to the frame.

Due to the fundamentally same structure, the following statements apply to the exemplary embodiment of FIG 2 and 3 also for the embodiment of 4 , 5 and 6 .

In the Figures 2a and 2b is in each case the lower part 15, of which a longitudinal member 16 is shown, in the maximum lowered position, ie the lower part 15 and the upper part 13 comprising the working chamber is open. On the other hand, they show Figures 3a and 3b the state of the work station with the work chamber closed, in which the base 15 is in the maximum raised position.

The lifting mechanism is also provided here with an upper lift function for the upper part 13: With the chamber open according to the Figures 2a and 2b is the upper part 13 in the maximum raised position, whereas the maximum lowered position of the upper part 13 with the working chamber closed in the Figures 3a and 3b is shown.

The lower stroke movement of the lower part 15 and the upper stroke movement of the upper part 13 are forcibly coupled to one another via the shafts 17 and run in opposite directions to one another, ie raising the lower part 15 is associated with a lowering of the upper part 13 and vice versa. The shafts 17 are synchronized with one another via a synchronization coupler 43 which acts on the shafts 17 via a shaft crank 25 which is non-rotatably connected to the respective shaft 17 . The synchronization coupler 43 is articulated on the shaft cranks 25 so that it can pivot about a joint axis 81 .

The shafts 17, which are synchronized with one another, are rotated by means of a single electric motor 19, which acts on the shaft 17 on the left in the figures, namely via a motor crank 31 connected to a drive shaft 29 of the motor 19, which is articulated via a drive coupling 33 to the shaft crank 25 this shaft 17 is connected.

Starting from the open position according to the Figures 2a and 2b the motor 19 rotates the motor crank 31 counterclockwise by about 150°, as a result of which all the shaft cranks 25 synchronously also rotate counterclockwise together with the shafts 17, namely by a rotation angle of about 100°. Consequently, there is a gear reduction between the motor crank 31 and the shafts 17 .

The rotation of the motor cranks 25 is converted into a movement of the two push rods 23, whereby the relevant longitudinal beam 16 of the lower part 15 is moved upwards.

As already mentioned elsewhere, the structure of the two individual gears at the left end and at the right end of each shaft 17 is identical, i.e. each shaft 17 engages at two transversely spaced points with an arrangement of motor crank 25 and push rods 23 on the relevant longitudinal beam 16 of the lower part 15. The motor 19, on the other hand, is only connected via the motor crank 31 and the drive coupling 33 to the shaft crank 25 at the rear in the side view chosen here.

The design of the lifting mechanism chosen in the two exemplary embodiments described here is advantageous in several respects:
With the working chamber closed according to the Figures 3a and 3b are each of a shaft crank 25 and the associated push rods 23 formed toggle lever assemblies each in a vertically extended position. The bottom 15 consequently exerts no torque on the shafts 17 in this neutral position of the transmission. The entire effective weight force is derived directly via the shafts 17 and the support rollers 35 connected to the shafts 17 into the longitudinal beams 37 and thus into the frame of the work station.

In the open position of the working chamber according to the Figures 2a and 2b the four-bar linkage formed by the drive shaft 29 of the motor 19, the motor crank 31, the drive coupling 33 and the shaft crank 25 is also in a neutral position in the sense of a stretched state in which the relevant axes lie in a common plane. The relevant axes are the axis of rotation 65 of the drive shaft 29 of the motor 19, the joint axis 63 between the motor crank 31 and the drive coupling 33, and the joint axis 67 between the drive coupling 33 and the shaft crank 25. This stretched state has the consequence that the shaft crank 25 can no longer rotate clockwise, the total effective weight of the lower part 15 and the transmission consequently cannot exert any torque on the drive shaft 29 of the motor 19. With the working chamber open, ie with the lower part 15 lowered to the maximum, the motor 19 is thus free from external forces. Consequently, the motor 19 does not need to be supplied with a holding current in order to generate a torque counteracting a weight force. In particular, when the working chamber is open, it is possible, if necessary, to exchange the motor 19, which is free of forces in this respect, without any problems, or to separate it from the motor crank 31 for other reasons.

In addition, the moving parts and their connections are optimally designed and arranged relative to one another in such a way that, with the inclusion of an upper stroke movement of the upper part 13, which will be explained in more detail below, an optimal force or torque curve without disadvantageous force or torque peaks over the entire opening or Closing movement of the working chamber, ie over the entire angle of rotation of the motor crank 31 or the shafts 17, results.

In relation to the shafts 17 and thus to a reference system of only the lifting mechanism, the movement sequence of the lower part 15 described above is independent of the manner in which the lifting mechanism is supported on the frame 11 (cf. 1 ) or on the support profiles 37 of the frame. On the other hand, in relation to the frame 11 supported on the floor and thus to the foil plane 55, which assumes a fixed height position in relation to the frame 11, the maximum stroke of the lower part 15 relative to the shafts 17 (as mentioned in the introductory part, for example 105 mm) does not correspond to the effective working stroke of the working chamber ( eg 80mm). The reason for this is that the rotation of the shafts 17 caused for the execution of the lower stroke of the lower part 15 results in a lowering of the shafts 17 at the same time. The lowering of the shafts 17 results in a downward movement of the entire lifting mechanism, including the upper part 13 supported on the shafts 17 via the columns 27, relative to the frame and thus relative to the film plane 55. The upper stroke is 25mm, for example, so that the maximum effective working stroke mentioned of 105mm - 25mm = 80mm, which is designed to be sufficiently large for applications with a required effective working stroke of the working chamber of around 75mm.

The shafts 17 are lowered by eccentric mounting of the shafts 17 on the support rollers 35 . This concept can be illustrated particularly well with the Figure 2a and 3a be understood, in each of which the support roller 35 is not shown on the left gear. Instead, it can be seen there that the axes of rotation 18 of the shafts 17 do not coincide with the axes of rotation of the support rollers 35 , also referred to below as eccentric axes 36 . The eccentricity, ie the radial distance between the axis of rotation 18 of the shaft 17 and the eccentric axis 36 determines--at a given maximum angle of rotation of the shaft 17--the maximum stroke of the upper stroke.

With the working chamber closed according to Figure 3a , i.e. in the stretched state of the toggle lever arrangement consisting of shaft crank 25 and connecting rods 23, the eccentric axes 36 also lie in the common vertical plane of joint axis 71, joint axis 73 and shaft axis of rotation 18. The eccentric axes 36 each lie vertically above the axis of rotation 18 of the relevant shaft 17, ie the shafts 17 and thus the entire lifting mechanism, in particular including the upper part 13, are lowered to the maximum with respect to the frame.

With the chamber open according to Figure 2a on the other hand, the shafts 17 and thus the upper part 13 are maximally raised with respect to the frame, starting from an angle of 0° with the chamber closed according to FIG Figure 3a a common plane of shaft axis of rotation 18 and eccentric axis 36 encloses the above-mentioned angle of approximately 100° to the vertical. This angle is the maximum angle of rotation of the shafts 17.

Since the entire lifting mechanism is firmly connected to the spindle 39 and thus to the frame in the longitudinal direction via the spindle nut 41 interacting with the right-hand column 27, the evasive movement in the longitudinal direction required due to the eccentric movements of the shafts 17 around the support rollers 35 is not caused by the lifting mechanism, but carried out by the support rollers 35, which roll for this purpose on the carrier profiles 37 of the frame. This can for example in the Figure 2a and 3a can be understood particularly well on the basis of the positions of the rollers 35 in the longitudinal direction relative to the columns 27 fixed in the longitudinal direction.

At the same time, the support rollers 35 enable the lifting mechanism to be positioned in the longitudinal direction by manually rotating the spindle 39, as has already been described above.

In this respect, the lifting mechanism is a carriage that can be moved in the longitudinal direction on the carrier profiles 37 of the frame with wheels formed by the support rollers 35 arranged eccentrically with respect to the axes of rotation 18 of the shafts 17 and with a stable base formed by the frame comprising the longitudinal beams 20 and the transverse beams 22. The shafts 17 are rotatably mounted in this base, which thus carry the upper part 13 via the columns 27 and the longitudinal beams 20 and the lower part 15 via the gears formed by the shaft crank 25 and the push rods 23 in each case.

The above statements apply in principle to the embodiment of 4 , 5 and 6 , which show a lifting mechanism according to the invention with only two shafts 17. In principle, the concept of the lifting mechanism according to the invention and its arrangement and support in a frame of a respective work station, as described here, can be applied to any number of shafts 17 arranged one behind the other in the longitudinal direction.

while in the Figure 4a , 5a and 6a in each case the open state is shown with the lower part 15 lowered to the maximum and the upper part 13 raised to the maximum, show the Figure 4b , 5b and 6b the status of the lifting mechanism when the chamber is closed.

Furthermore, in 4 and 6 one of the two carriers 16 of the lower part 15 connecting, plate-shaped cross brace 45 for the lower part 15 is shown.

The carrier 16 and the cross strut 45 of the lower part 15 and the longitudinal elements 59 of the upper part 13 represent functional blocks for the lower chamber and the upper chamber (not shown) and are provided with the electrical and pneumatic connections and connections required for the operation of the working chamber.

Furthermore, the illustrations in Figures 6a and 6b In particular, the symmetrical structure of the individual gears can be seen, in which the carrier 16 of the lower part 15 and the shaft crank 25 are arranged between the pair of push rods 23. This simplifies the design of the rotary bearings between the connecting rods 23 and the carrier 16 on the one hand and the connecting rods 23 and the shaft crank 25 on the other hand, since tilting moments and the transverse forces resulting therefrom are avoided or at least minimized. The guide tabs 61 for the vertical guidance of the lower part 15 on the columns 27 can consequently be of comparatively simple design. This also underlines the extremely robust and low-maintenance overall structure of the lifting mechanism.

Furthermore, in particular the representations in the 4 and 6 It can be seen that the moving parts for raising and lowering the lower part 15 and the rollers 35 eccentrically mounted on the shafts 17 for supporting the entire lifting mechanism on the frame and for performing the upper lift are arranged relatively far to the side and are therefore easily accessible. In addition, this makes the interior of the lifting mechanism available for other purposes, in particular for tool-specific components and connecting lines.

A further advantage of the lifting mechanism according to the invention is that the integration of the upper lifting movement does not mean any significant additional effort, but only requires the explained eccentric connection between the shafts 17 and the support rollers 35 instead of a central connection which is also possible in principle.

reference list

11

frame

13

top

15

lower part

16

carrier of the lower part

17

Wave

18

axis of rotation of the shaft

19

drive motor

20

side members

21

base, frame

22

cross member

23

push rod

25

shaft crank

27

pillar

29

drive shaft

31

engine crank

33

drive coupler

35

supporting organ, role

36

eccentric axis

37

carrier profile

39

spindle

41

spindle nut

43

synchronization coupling

45

cross brace

51

support profile

53

transverse element

55

slide level

57

stand

59

longitudinal element

61

tab

63

joint axis

65

axis of rotation

67

joint axis

71

joint axis

73

joint axis

81

joint axis

Claims (11)

Workstation, in particular deep-drawing station, forming station, sealing station, cutting station or stamping station, for a packaging machine - a frame (11) supported on the ground, - a working unit comprising an upper part (13) and a lower part (15), and - a lifting mechanism carried by the frame (11) with which the lower part (15) of the working unit can be raised and lowered relative to the frame (11) to carry out a lower lift, wherein the lifting mechanism has a drive which has at least one shaft (17) extending in the transverse direction, a drive motor (19) acting on the shaft (17) for rotating the shaft (17) and at least one gear coupled to the shaft (17) on the input side (23, 25, 61, 71) on which the lower part (15) is supported on the output side and which converts a rotation of the shaft (17) into the lower stroke of the lower part (15), the upper part (13) being used to carry out an upper stroke can be lowered and raised relative to the frame (11), and
the shaft (17) being mounted eccentrically on the frame (11) with respect to its axis of rotation (18). Workstation according to claim 1,
the upper part (13) being supported on the frame (11) via the lifting mechanism. Workstation according to claim 1 or 2,
the upper part (13) being supported on the frame (11) via the shaft (17). Workstation according to one of claims 1 to 3,
the upper part (13) being supported on a base (21) of the lifting mechanism, preferably comprising a frame, and the shaft (17) being rotatably mounted in the base (21). Workstation according to one of Claims 1 to 4,
At least two support members (35) spaced apart along the shaft (17) are provided to support the shaft (17) on the frame (11), on which the shaft (17) is mounted eccentrically with respect to its longitudinal axis. Workstation according to claim 5,
the support members (35) being movably supported in the longitudinal direction on the frame (11). Workstation according to claim 5 or 6,
the support members (35) being capable of an evasive movement in the longitudinal direction in order to carry out the upper lift when the shaft (17) is fixed in the longitudinal direction relative to the frame (11). Workstation according to one of claims 5 to 7,
the support members (35) each comprising a roller or roller. Workstation according to one of claims 1 to 8,
the lower stroke and the upper stroke being positively coupled to one another, in particular via a rotation of the shaft (17). Workstation according to one of Claims 1 to 9,
the lower stroke and the upper stroke running in opposite directions to one another. Packaging machine with at least one work station according to one of the preceding claims.

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