WO2005042349A1

WO2005042349A1 - Packaging machine comprising an electrolinear cylinder

Info

Publication number: WO2005042349A1
Application number: PCT/EP2004/012305
Authority: WO
Inventors: Frank Michel
Original assignee: Cfs Germany Gmbh
Priority date: 2003-11-03
Filing date: 2004-10-29
Publication date: 2005-05-12
Also published as: DE10351567A1; DE10351567B4

Abstract

The invention relates to a packaging machine in which at least one tool (4, 9, 11) can be moved into a lowered and a raised position with the aid of a means (50). Said tool is provided with at least one electrolinear drive unit (68) as a driving mechanism.

Description

Packaging machine with an electric linear cylinder

The present invention relates to a packaging machine in which at least one tool can be displaced with a means into a lowered and into a raised position, the tool having at least one electric linear drive as the drive.

Nowadays, food is often packed in plastic packaging to make it durable. The packaging is usually manufactured and filled using a semi-continuous working packaging machine, in which the packaging trough is first deep-drawn from a film, then filled with the goods to be packaged and then sealed with a cover film. The packaging produced in this way is cut apart in a final cut. In the production of the packaging, tools, for example the deep-drawing mold, the sealing and / or cutting tool, have to be moved vertically, with very considerable forces occurring in particular when sealing and cutting. In the past, the above-mentioned tools were usually driven with pneumatic cylinders because they are easy and inexpensive to use.

Since the food and medical technology industries are demanding ever higher hygiene standards for packaging machines and the atmosphere surrounding the packaging machine, pneumatically driven cylinders have proven to be disadvantageous because, on the one hand, the compressed air that drives the pneumatic cylinder is not germ-free overall and, on the other hand, it is contaminated by lubricants can.

It was therefore the object of the present invention to provide a packaging machine which is more hygienic than machines according to the prior art.

The object is achieved according to the invention with a packaging machine in which at least one tool with a means in a lowered or in a raised position is displaceable, and in which the tool has at least one electric linear drive.

It was extremely surprising for the specialist and it was not to be expected that this machine would meet much higher hygienic standards. The packaging machine is less expensive to operate and less noisy than packaging machines according to the prior art. The packaging machine according to the invention is simple and inexpensive to manufacture.

According to the invention, the packaging machine has an electric linear drive as drives for the tools present therein. An electric linear drive in the sense of the invention is a drive in which the electrical energy is converted into a linear movement of a piston or the like. The electric linear drive is preferably an electric cylinder, particularly preferably a cylinder with a spindle which interacts with a nut. There is preferably a certain pretension between the nut and the spindle, so that the spindle or the nut always abut a certain flank of the thread. This embodiment of the present invention has a particularly low backlash. Furthermore, the electric drive is preferably a linear motor, in which a rotationally permanently excited synchronous motor is preferably cut lengthways and unwound in one plane. The primary part of the linear motor preferably consists of a laminated core and a copper winding, the secondary part of iron and permanent magnets.

The electric linear cylinder can drive any gear, for example a crank, cam or articulated gear as well as a combination of these types of gear. In a preferred embodiment of the packaging machine according to the invention, the electric linear drive drives a toggle lever system, which in turn causes the up and down movement of the respective tools.

A tool in the sense of the invention is any tool that is used to produce packaging and that has to be moved up and down. For example, the tool is a deep-drawing mold, a sealing tool and / or a cutting tool. at A tool in the sense of the invention can be located below or above the film web from which the packaging tray is manufactured.

The electric linear drive can be controlled in any way known to the person skilled in the art. Preferably, the electric linear drive, in particular if it is an electric linear cylinder, is operated with two limit switches, so that it moves the respective tool between two limit positions. In another preferred embodiment, the electric linear drive and / or the means, which is arranged between the electric linear drive and the tool, is provided with a sensor which transmits the position of the drive or means to a computer which determines the movement of the tool based thereon Position regulates. This regulation allows not only to move the tool between two end points, but also to be able to adjust the raised or lowered position as desired. Furthermore, this drive enables the speed of the linear drive to be specifically changed between the two positions.

A packaging machine in the sense of the invention is not only a thermoformer, in which the packaging trough is produced by deep drawing and then filled and sealed with a cover film, but also a so-called traysealer, in which preformed packaging troughs are filled with a packaging material and then sealed with a packaging film become. Furthermore, a packaging machine in the sense of the invention is also a so-called tray former, in which only packaging troughs are deep-drawn from a film and then cut apart.

The invention is explained below with reference to FIGS. 1 and 2. These explanations are only examples.

Figure 1 shows the basic structure of a thermoforming packaging machine.

Figure 2 shows a perspective view of a toggle lever system 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 work stations each have tools which - previously also referred to as lower tools 4, 9, 11 - can be raised or lowered and which 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 at a work station above the Lifting parts 4, 9, 11 are arranged. According to the invention, the lifting parts are raised or lowered compared to the stationary parts by means 50. The means 50 are also referred to below as a 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 FIG. 2. The lifting table 50 is provided in accordance with the invention in particular in such a way that it can be attached by means of several suspension points 54, for example four suspension points 54, in the horizontally extending one in FIG 2 mounting rail 15, not shown, can be inserted horizontally. 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. 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 firmly connected to the support rods 52. However, the yokes 66 can also be axially displaceable and supported on a spring element in order to compensate for film thickness fluctuations and to avoid that the packaging machine is damaged when the outward stroke is too great. The spring force in this embodiment is somewhat greater than the desired seal or cutting force. The cantilevers 64 and the rods 63 form toggle lever systems which rotate the lifting shafts 65a, 65b in a translatory or linear movement of the plate 5 and thus the lifting parts 4, 9, 11 relative to that in FIGS. 2 to 4 Convert stationary part, not shown. 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 by means of an electric cylinder 68 (Parker Hannifin GmbH Germany) which has a first point of application and a second point of application. 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 FIG. 2, 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 electric cylinder 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 if the extension of the electric cylinder 68 causes the lifting shafts 65a, 65b to rotate and the knee 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 possibility of 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 between the lifting shafts 65a, 65b is provided. Compensating means which cause 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 of the electric cylinder 68 is transmitted directly and evenly 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 uniquely determined by the extended or retracted state of the electric cylinder 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. In a particularly advantageous embodiment, the wire 71 is provided with a tensioning means or a spring means 70, for example a spiral spring that can be expanded linearly along its axis, the wire 71 being provided in a crossed manner 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 attached in this way the wire 71 or on the lifting shafts 65a, 65b, it is provided that the spring means 70 is deflected when the plate 5 is raised. 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.

Those skilled in the art will recognize that the linear electric drive can be used alone to bring the respective tools into a raised or lowered position. The person skilled in the art further recognizes that the linear electric drive can interact with any gear known to the person skilled in the art, for example a crank, cam or articulated gear as well as a combination of these types of gear, that translates a linear movement into an up and down movement.

LIST OF REFERENCE NUMBERS

1 film 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 lifting actuator 61 guide bushes 62 bearings 63 rods 63a / 63b upper / lower ends of rods 64 boom 65a / 65b first / second lifting shaft 66 yoke 67a / 67b first / second lever 68 electric cylinder 69 arrow 70 spring means 71 wire

Claims

claims:

1. Packaging machine, in which at least one tool (4, 9, 11) can be displaced with a means (50) into a lowered and into a raised position, characterized in that the tool has at least one electric linear drive as the drive (68).

2. Packaging machine according to claim 1, characterized in that the electric linear drive is an electric linear cylinder

3. Packaging machine according to one of the preceding claims, characterized in that means (50) is a toggle lever.

4. Packaging machine according to one of the preceding claims, characterized in that the tool is a deep-drawing mold, a sealing tool and / or a cutting tool.

5. Packaging machine according to one of the preceding claims, characterized in that the electric linear drive can be controlled by limit switches.

6. Packaging machine according to one of claims 1-3, characterized in that the movement of the tool (4, 9, 11) can be controlled by a computer.