WO2004110871A1 - Working station and packaging machine - Google Patents

Abstract

A working station, in particular for a packaging machine and a packaging machine are disclosed, whereby the working station (2, 7, 10) has a stationary part (3, 8, 12), a lifting part (4, 9, 11) and a lifting device (50). The lifting device is provided for the linear movement of the lifting part relative to the stationary part along guide means (51). Said lifting device comprises a first lifting shaft (65b) and a second lifting shaft, the lifting shafts each being provided with a toggle joint. A linear actuator is provided with a first and a second connection point. Said linear actuator is provided to carry out the linear movement of the lifting part by means of a rotating movement of the lifting shafts. The first lifting shaft provides the first connection point for the linear actuator and the second lifting shaft provides the second connection point for the linear actuator and balance means (61, 70, 71) are provided to ensure an even movement of the lifting shafts.

Description

Work station and packaging machine

The invention relates to a work station, in particular for a packaging machine, and a packaging machine. Such a work station is used in a known manner as a component of packaging machines and in particular of vacuum packaging machines. Because of the forces that occur during operation, the known workstations are very heavy.

For example, from European patent EP 0569 937 B1 a packaging machine with a work station is known in which the work station has a lifting device in which the lower tool is raised or lowered by a toggle lever system and a piston-cylinder device. The piston-cylinder device is only connected to one of two toggle lever systems, so that an additional parallel rod is required to actuate the other toggle lever system. The known lifting device therefore requires a lot of space, so that the dimensions of the packaging machine are unnecessarily increased and the packaging machine is also unnecessarily heavier and more expensive. Furthermore, the known packaging machine is more difficult to operate in terms of maintenance and more prone to errors because a complicated mechanism is used.

It is therefore the task of providing a packaging machine which does not have the disadvantages of the prior art.

The object is achieved according to the invention by a work station and a packaging machine equipped with this, the work station being provided with a stationary part, a lifting part and a lifting device, the lifting device being provided for linear movement of the lifting part relative to the stationary part along guide means, the lifting device has a first lifting shaft, a second lifting shaft, a first toggle lever system and a second toggle lever system, the lifting shafts each having a toggle lever joint, a linear actuator having a first and a second engagement point being provided, the linear actuator being provided by means of a rotary movement of the lifting shafts to cause the linear movement of the lifting part, continuing as the the first stroke point of the linear actuator is provided, the second stroke shaft being provided as the second point of attack of the linear actuator and compensation means being provided which bring about a uniform movement of the stroke shafts.

A workstation in the sense of the invention is e.g. a deep-drawing, a sealing and / or a cutting station. In the context of the invention, a linear actuator is to be understood as an actuator whose ends or the points of application carry out a linear movement relative to one another, i.e. in a retracted first state of the linear actuator, the points of engagement are at a minimum distance from one another and the points of attack are at a greatest distance from one another in an extended second state of the linear actuator.

In a preferred embodiment, the first point of application is provided on a lever attached to the first lifting shaft and the second point of application is provided on a lever attached to the second lifting shaft. As a result, the linear actuator can be attached to the two lifting shafts or the two toggle lever systems using very simple and inexpensive means. The linear actuator is preferably provided as a piston-cylinder device, the piston-cylinder device being operable in particular electrically and / or pneumatically and / or hydraulically. This has the advantage that proven technology of the linear actuator can be used in a cost-effective manner. In particular, it is advantageously provided according to the invention to use a servo actuator that reports its position as a linear actuator. In this case, it is advantageously possible for the linear actuator (and thus the lifting part) to pass through only partial areas of its entire possible range of movement, so that the clock frequency of the movement of the lifting part can be increased, which leads to an increase in the efficiency of the packaging machine. In a preferred embodiment of the invention, the linear actuator is also provided as a spindle drive.

In a preferred embodiment, the compensating means are provided in such a way that a uniform and opposite movement of the lifting shafts is brought about by the compensating means. This is particularly advantageous if the levers provided for moving the toggle lever systems, on which the linear actuator is provided, and the attachment of the points of application of the linear actuator are provided in the same manner, ie essentially symmetrically. In this case, a uniform but opposite movement of the lifting shafts leads to a uniform lifting of the lifting part with respect to both toggle lever systems. The compensating means are preferably provided as a chain and / or as a toothed belt and / or as a plurality of toothed wheels and / or as a wire. This has the advantage that a simple and inexpensive, because proven measures, a light and space-saving construction of the workstation is possible. As an alternative or in addition to such direct compensating means which directly intervene in or influence the movement of the lifting shafts, it is furthermore provided according to the invention in a preferred embodiment to provide the compensating means as indirect compensating means, in particular providing the (indirect) compensating means advantageously as guide elements of the lifting part is. This has the advantage that the lifting part (with additional use of the indirect compensating means) is raised in a more even manner or that the even and non-tilting lifting of the lifting part (with alternative use of the indirect compensating means) is done with very simple, so cost-effective and still robust means is possible, for example by means of guide sleeves which are provided on the lifting part and which result in guidance with simultaneous horizontal alignment of the lifting part.

The invention is explained below with reference to FIGS. 1-4. These explanations are only examples and do not limit the general inventive concept.

Show it:

Figure 1 is a schematic side view of a packaging machine with the side cover omitted;

Figure 2 is a perspective view of the lifting table in the raised position; Figure 3 is a front view of the lifting table in the raised position and

Figure 4 is a side view of the lifting table in the raised position.

Figure 1 shows the packaging machine according to the invention in a schematic representation. A film 1 is rolled off a roll and first passes through a deep-drawing station 2, which consists of an upper tool 3 and a lower tool 4. The lower tool 4 is mounted on a plate 5 which, as indicated by the arrow, can be raised and lowered. In the thermoforming station 2, the film 1 is deformed into a packaging trough 6.

The packaging troughs 6 are then filled with a product to be packaged and in the following sealing station 10 the packaging troughs are sealed with a cover film. The sealing station 10 also consists of an upper tool 12 and a lower tool 11, wherein the lower tool 11 can also be raised and lowered at the sealing station.

Finally, the packaging is cut apart in the cutting station 7. The cutting station 7 also consists of an upper tool 8 and a lower tool 9, and the lower tool 9 can also be raised and lowered at the cutting station.

The deep-drawing station 2, the sealing station 10 and the cutting station 7 are also referred to below as work stations 2, 10, 7. The work stations each have tools which - previously also referred to as upper tools 3, 8, 12 - are stationary or can be raised and are referred to below as stationary parts 3, 8, 12. The workstations 2, 10, 7 can in particular be fastened to one or more rails (not shown in the following) which run essentially horizontally (hereinafter also referred to as mounting rails 15) by means of so-called suspension points which are attached to the workstations 2, 10, 7. The work stations can in particular be provided on the rails so as to be horizontally displaceable. The workstations each have tools which - previously also referred to as lower tools 4, 9, 11 - lift are lowerable and are referred to below as lifting parts 4, 9, 11. It is expedient, but not absolutely necessary according to the invention, that the lifting parts 4, 9, 11 are arranged at a work station below the stationary parts 3, 8, 12. It is also appropriate, but not necessary according to the invention, that the stationary parts 3, 8, 12 are arranged at a work station above the lifting parts 4, 9, 11. According to the invention, the lifting parts are raised or lowered compared to the stationary parts by means of a lifting device. The lifting device is also referred to below as a lifting table.

The lifting table with which the lifting parts 4, 9, 11 are lowered and raised is shown in FIGS. 2, 3 and 4, which each allow a different view of the raised lifting table. Figure 2 shows a perspective view of the lifting table, while Figure 3 shows a front view and Figure 4 shows a side view of the lifting table.

The lifting table 50 has a plate 5 on which the lifting parts 4, 9, 11 can be mounted. The plate 5 is provided with two guide bushes 61 which receive guide rods 51. Further support rods 52 carry a fastening device 53 for the stationary part 3, 8, 12, which is not shown in FIGS. 2, 3 and 4. The lifting table 50 is in particular provided according to the invention in such a way that it is horizontal by means of several suspension points 54, for example four suspension points 54 extending mounting rail 15, not shown in Figures 2 to 4 can be used horizontally displaceable. The fastening device 53 and thus the stationary part 3, 8, 12 can, in a preferred embodiment of the lifting table 50, be provided so as to be vertically displaceable relative to the suspension points 54. Such a vertical displacement or movement of the stationary part 3, 8, 12 is provided, for example, by means of a stroke actuator 55, which is provided in particular as an electric motor, for example by means of a spindle drive, or the like. According to the invention, the support rods 52 can also - in addition to their function as support rods 52 - perform a function as guide rods for the plate 5 or the lifting part 4, 9, 11. In this case, provision can be made to dispense with additional guide rods 51 and to use the support rods 52 as guide rods 51. On its lower side, the plate 5 has bearings 62, in which upper ends 63a of rods 63 are pivoted about axes are. The rods 63 are rotatably connected at their lower end 63b via a boom 64 to a first lifting shaft 65a or to a second lifting shaft 65b, the lifting shaft itself being rotatably supported in yokes 66. The yokes 66 are non-positively connected to the rods 52. The arms 64 and the rods 63 form toggle lever systems which convert a rotary movement of the lifting shafts 65a, 65b into a translatory or linear movement of the plate 5 and thus of the lifting parts 4, 9, 11 relative to the stationary part not shown in FIGS. 2 to 4. Here, the first toggle lever system is attached to the first lifting shaft 65a and the second toggle lever system is attached to the second lifting shaft 65b. Here, the first toggle lever system can include a plurality of toggle levers provided on the first lifting shaft 65a. Likewise, the second toggle lever system can comprise a plurality of toggle levers that are provided on the second lifting shaft 65b. In the example of FIGS. 2 to 4, two toggle levers are provided on each of the two lifting shafts 65a, 65b. The first and second lifting shafts 65a, 65b are moved according to the invention by means of a linear actuator 68 having a first point of action and a second point of action, which is provided in particular as a piston-cylinder device 68. For this purpose, a first lever 67a is provided on the first lifting shaft 65a and a second lever 67b on the second lifting shaft 65b. The first point of application is provided at the end of the first lever 67a facing away from the first lifting shaft 65a and the second point of application is provided at the end of the second lever 67b facing away from the second lifting shaft 65b. In the extended state of the lifting device 50 shown in FIGS. 2, 3 and 4, the lifting part 4, 9, 11 and the plate 5 are in their / their highest position because the arms 64 and the supports 63 are each arranged essentially linearly one behind the other. In this situation, the linear actuator 68 is completely retracted in the exemplary embodiment shown, ie the points of attack are at the smallest distance. The plate 5 and thus the lifting part 4, 9, 11 are lowered when the linear actuators 68 extend the rotation of the lifting shafts 65a, 65b, causing the toggle lever systems to buckle. This movement is indicated in FIG. 2 by means of the arrows 69. According to the invention, this movement is carried out uniformly for both lifting shafts 67a, 67b or for both toggle lever systems, so that there is no tilting of the plate 5. For this purpose, compensating means are provided on the lifting device 50 according to the invention. A first option such compensating means is to provide the guide bushes 61. The longer the guide bushes 61 are provided, the better the guidance of the lifting part 4, 9, 11 in the guide rods 51 and thus its protection against tilting. Another possibility of such compensating means is to ensure a synchronized and opposite movement of the lifting shafts 65a, 65b by, for example, a link chain, a toothed belt, a gear arrangement, a wire - in particular wound on the lifting shafts 65a, 65b - or a combination thereof Means is provided between the lifting shafts 65a, 65b. Compensating means which bring about a synchronized movement of the lifting shafts 65a, 65b by means of gearwheels, chains or the like directly on the lifting shafts, ie, with the same effective boom lengths on both toggle lever systems, in particular a uniform and opposing movement, are also referred to below as direct compensating means. An example of such direct compensation means is shown in Figure 4. In the area of the yoke 66 between the lifting shafts 65a, 65b, a wire 71 is connected in a crossed manner to the lifting shafts 65a, 65b, in particular wound up by means of one or more revolutions, in such a way that the wire 71 is made in an opposite direction, that is, with a different sense of rotation. rotative movement of the lifting shafts 65a, 65b unwound from one lifting shaft above and at the same time wound onto the other lifting shaft below or vice versa. This ensures that the force effect of the linear actuator 68 is transmitted directly and uniformly to both toggle lever systems. For example, larger frictional resistances of one system are compensated for by the compensating means. This ensures that the movement of the lifting device has only one degree of freedom and that the height of the plate 5 is unambiguously determined by the extended or retracted state of the linear actuator 68. Compensating means that indirectly cause a synchronized movement of the lifting shafts, such as, for example, extended guide bushes 61, are also referred to below as indirect compensating means. According to the invention, direct and indirect compensating means are used both cumulatively and alternatively. It is important to ensure that the compensating means have as little slip as possible. This can be accomplished, for example, by providing spring means integrated in the compensating means. The wire 71 is in a particularly advantageous embodiment with a clamping means or a spring means 70, for example a spiral spring that is linearly expandable along its axis, the wire 71 being crossed between the lifting shafts 65a, 65b and the spring means 70 tensioning the wire 71. In the example shown in FIG. 4, the spring means 70 is provided, for example, in such a way that any slippage of the compensating means provided as wire 71 is prevented. In an alternative embodiment, not shown in FIG. 4, the wire 71 is provided with a tensioning means or a spring means 70, which is provided on the wire 71 or on the lifting shafts 65a, 65b in such a way that when the plate 5 is lifted, it becomes a Deflection of the spring means 70 comes. In a further embodiment of the invention, not shown, it is provided to provide a chain or a toothed belt crossed between the lifting shafts 65a, 65b. In this case, a counter-rotating movement of the lifting shafts 65a, 65b can be effected with particularly simple means.

LIST OF REFERENCE NUMBERS

1 slide

2, 7, 10 work stations

3, 8, 12 stationary part / upper tool

4, 9, 11 lifting part / lower tool

5 plate

6 packaging tray

15 mounting rail

50 lifting device / lifting table

51 guide rods

52 support rods

53 fastening device

54 suspension point

55 stroke actuator

61 guide bushes

62 bearings

63 bars

63a / 63b upper / lower ends of rods

64 outriggers

65a / 65b first / second lifting shaft

66 yoke

67a / 67b first / second lever

68 linear actuator

69 arrow

70 spring means

71 wire

Claims

claims 1. work station (2, 7, 10), in particular for a packaging machine, with a stationary part (3, 8, 12), a lifting part (4, 9, 11), and a lifting device (50), the lifting device for linear movement the lifting part (4, 9, 11) is provided relative to the stationary part (3, 8, 12) along guide means (51), the lifting device (50) having a first lifting shaft (65a), a second lifting shaft (65b), and a first one Having a toggle lever system and a second toggle lever system, a linear actuator (68) having a first and a second point of application being provided, the linear actuator (68) being provided, by means of a rotary movement of the lifting shafts (65a, 65b), the linear movement of the lifting part (4 , 9, 11), characterized in that the first stroke point (65a) is provided as the first point of attack of the linear actuator (68) and that the second stroke shaft (65b) is provided as the second point of attack of the linear actuator (68), wherein Compensating means (61, 70, 71) are provided which bring about a uniform movement of the lifting shafts (65a, 65b). 2. Work station (2, 7, 10) according to claim 1, characterized in that the first engagement point is provided on a lever (67a) attached to the first lifting shaft (65a) and that the second engagement point is provided on a lever on the second lifting shaft (65b ) attached lever (67b) is provided. 3. Work station (2, 7, 10) according to one of the preceding claims, characterized in that the linear actuator (68) is provided as a piston-cylinder device which can be operated in particular electrically or pneumatically or hydraulically, the piston-cylinder device in particular being electrically and / or can be operated pneumatically and / or hydraulically. 4. Work station (2, 7, 10) according to one of the preceding claims, characterized in that the linear actuator (68) as a servo actuator, in particular with a cylinder and in particular with a spindle, is provided. 5. Work station (2, 7, 10) according to one of the preceding claims, characterized in that the compensating means (61, 70, 71) are provided as a uniform and counter-rotating movement of the lifting shafts causing compensating means (61, 70, 71). 6. Workstation (2, 7, 10) according to one of the preceding claims, characterized in that the compensating means (61, 70, 71) comprise a chain and / or a toothed belt and / or a plurality of toothed wheels and / or a wire. 7. Work station (2, 7, 10) according to one of the preceding claims, characterized in that the compensating means (61, 70, 71) are provided as indirect compensating means, in particular as guide elements of the lifting part. 8. Packaging machine with at least one work station (2, 7, 10) according to one of the preceding claims.