RU2291053C2 - Device for moulding polymeric film articles - Google Patents

Abstract

FIELD: shaping plastics.

SUBSTANCE: device comprises mould made of top tool table provided with top tool and movable bottom tool table provided with bottom tool. The movable bottom tool table is set in the guiding means and is actuated by the first driving device. The top tool table has first driving device for mounting the top tool table. The top tool table has second driving device for actuating the means for preliminary tension mounted in the top tool . The bottom table together with the first driving device can move vertically within the guiding device.

EFFECT: improved quality of articles.

9 cl, 11 dwg

Description

The present invention relates to a thermoforming installation for the manufacture of molded products from a polymer film, such as cups, containers, lids, food packaging and the like, with a thermoforming unit having a two-part shape, according to the preamble of paragraph 1 of the claims, and to a method of manufacturing such molded products, according to the restrictive part of paragraph 7 of the claims.

Thermoforming plants are known in practice in different versions and forms of execution. In this case, for the manufacture of molded products in the form of cups from thermoplastic, a composite form is used. One half-mold, the so-called upper tool, is mounted on the tool table and connected to it, as a rule, with the possibility of adjusting the frame or bed of the thermoforming installation, so that the upper tool can be adjusted to the corresponding manufactured molded product. Another half-mold, the so-called lower tool, is movably mounted in the frame or on the base of the thermoforming installation.

For molding half-mold products, i.e. the upper and lower tools are in the closed position facing each other. Between the upper and lower tools, a frequently heated and, thus, well plastically deformable polymer film is located, which in most cases is tactfully fed from the consumable roller in the form of a web.

During the deep drawing process, the polymer film is clamped between the upper and lower tools and, thus, is fixed in this position. Then, the polymer film is pressed into the cavity of the lower tool by means of a preliminary drawing device of the upper tool, while the edge of the manufactured molded product remains sandwiched between the upper and lower tools. By creating a vacuum in the cavities or by blowing in air, the film adheres to the inner walls of the cavities of the lower tool and thereby assumes the desired shape.

After sufficient cooling of the polymer film due to contact with the surface of the tool, actively cooled, if necessary, the molded products are separated from the polymer film. To do this, the lower tool is moved upwards by approximately the size of the film thickness. Corresponding cutting edges of the composite shape are cut out of the individual molded products from the film web. The remaining film grating is also often served tactfully to the winding unit.

To extract the molded products from the cavities, the lower tool is then moved away from the upper tool and thus rotated around its longitudinal axis so that the lower tool is directed towards the stacker and, thus, the molded products can be transferred to the stacker.

Examples of the thermoforming plants described above, known from practice, are described, for example, in US 6,135,756 or DE 3346628 A1.

These known thermoforming plants, however, have the significant economic disadvantage that they can be used to realize only low clock frequencies, for example, up to about 30 cycles per minute. Higher clock speeds are not possible without damage to moving parts. These low clock speeds, however, are no longer acceptable due to the high pressure costs present today.

In addition, the drawbacks are the drives used in the known thermoforming plants for the pre-stretching device movably located in the upper tool, since only low clock frequencies can be realized with them, for example, up to about 30 cycles per minute. In addition, the known thermoforming plants have the disadvantage of insufficient accuracy when adjusting or adapting the upper tool in relation to manufactured molded products.

The thermoforming machine described in DE 3346628 A1 operates in a composite form, the upper tool being fixedly mounted on the bed and the lower one movable. The lower tool is oriented for closing or opening in a combined lifting and pivoting movement to and from the upper tool and at the same time to the stacker and is directed back from it to the upper tool. The lifting and turning movement of the lower tool is created by means of a cam-disk and crank articulated mechanism. The lower tool must, therefore, be moved vertically and simultaneously rotate around its own longitudinal axis.

The combination of a crank articulated mechanism with a cam-disk drive used in the thermoforming machine known from DE 3346628 A1 is very complicated. In this case, the cam-disk drive already has that system drawback as such that only limited efforts can be transmitted with it. In addition, with the help of a cam-disk drive, it is impossible to realize high clock frequencies. In addition, cam-disk drives are prone to rapid wear, so they require frequent maintenance, which dramatically increases operating costs for such a thermoforming installation. In addition, the thermoforming machine considered here according to DE 3346628 A1 with its complex crank hinge mechanism contains an additional unit that also allows only low clock frequencies, due to its design.

More detailed information on the execution of the drive of the pre-exhaust device in DE 3346628 A1 is missing. Thus, it should be assumed that the drive of the pre-exhaust device not discussed here in detail does not allow higher clock frequencies than the lower tool drive, the clock frequency of which has already been considered above as too low.

The thermoforming machine according to US 6135756 also contains a composite mold. Here, the guiding device is also combined with the drive device of the lower tool table or lower tool and, due to the cam-disk and crank mechanism, provides combined lifting and turning movement of the lower tool, and there are two cam-disk and crank-mounted on the outer end faces of the lower tool connecting rod mechanism. In this case, the lower tool contains on its outer sides three trunnions that move in the corresponding cam grooves on the bed. These cam grooves have an extremely complex geometry and are capable of moving the lower tool when opening the mold down from the upper tool and turning so as to orient it to the stacker and turn it away from it again. Since the complex geometry of the cam grooves is unsuitable for transmitting the necessary forces to separate the molded products from the polymer film, additional cam discs are provided by means of which the forces necessary for this should be transmitted. The separation process achieved by this remains sharp or breaking off. You can’t talk about cutting down.

Geometrically complex and very difficult to coordinate cam-groove guides exclude the high clock frequencies required today.

The drive of the pre-exhaust device is described in US 6,135,756 as a combination of a gear rack and a gear wheel. This cannot realize the high clock frequencies necessary for the cost-effective operation of a modern thermoforming unit. To achieve a constantly repeatable high clock frequency, not only high clock frequencies are required when closing and opening the mold, but parallel to this, at least equally, the lifting movement of the pre-exhaust device must be accelerated so that the pre-exhaust device can be operated in the same measure as the form.

In addition, in practice, drives of pre-exhaust devices are known in which pre-exhaust devices are driven by ball screws. With such ball screws, the required high clock speeds are unattainable. In addition, ball screws are too expensive, require frequent maintenance, and have an additional disadvantage of high loss of working time.

As a consequence of this, the object of the present invention is to improve the known thermoforming machines in such a way that substantially higher clock frequencies can be achieved and thereby ensure the economical operation of thermoforming machines thus improved. A further object of the present invention is to provide an economical method for manufacturing molded articles from a polymer film.

This problem is solved in part of the device by the distinguishing features of paragraph 1 of the claims.

In terms of the method, the problem is solved by the distinguishing features of paragraph 7 of the claims.

According to the invention, there is provided a thermoforming apparatus for manufacturing molded articles from a polymer film, such as cups, containers, lids, food packaging and the like, with a thermoforming unit having a two-piece shape. At the same time, the two-part form contains an adjustable fixed upper tool table with an upper tool with movable preliminary extraction devices and a movable lower tool table with a lower tool with cavities. The movable lower tool table is guided by a guiding device and has the ability to move due to the drive device relative to the upper tool table to and from it.

In this case, for the first time, it is provided that the upper tool table comprises a first drive device matched with it for mounting the upper tool table in its position relative to the top dead center of the lower tool table in accordance with a correspondingly manufactured molded product, and a second drive device coordinated with it for driving movably mounted in the upper tool of the pre-exhaust devices.

In comparison with the drives of pre-exhaust devices known from the prior art, the separation of the drive of the pre-exhaust devices according to the invention due to the corresponding provision of a separate drive for this purpose, as well as an additional separate drive for adjusting or adjusting the upper tool with respect to the manufactured molded products before its final fixation, the start of the corresponding production process gives the advantage that both of these drives can be op are timisized independently of each other. Accordingly, it is possible to provide the most suitable drive for a one-time alignment or adjustment of the upper tool before the start of the corresponding production process, which preferably should not be forced to simultaneously realize the required high clock frequencies when the pre-exhaust device is driven, but can be specially selected with regard to accuracy and repeatability precise adjustment of the upper tool. Accordingly, a separate drive of the pre-exhaust device can be selected and optimized with respect to the required high clock frequency.

Although such separate optimization of separate drives increases the number of parts, it gives, in contrast, the invaluable advantage that both drives can be made structurally very simple and, therefore, ultimately inexpensive.

Other preferred embodiments and aspects of the present invention are the subject of the dependent claims.

In one preferred embodiment of the thermoforming installation, the first drive device for installing the upper tool table is in the form of an electric servomotor. It gives the advantage of precise control, and its speed profile can be chosen arbitrarily. Thus, both fast depth feed movements for overcoming large adjustment strokes, and especially slow and accurate depth feed movements for fine-tuning the upper tool table can be achieved in the millimeter range or even in the range of tenths of a millimeter depending on the desired accuracy. In addition, inexpensive electric servomotors are commercially available in any desired embodiment.

According to another preferred embodiment of the thermoforming installation, it is provided that this first drive device interacts via a synchronizing shaft with worms / wheels located on it, for example, via two adjusting spindles that are aligned with them, which, in turn, act on the upper tool table with the possibility of moving it in its horizontal orientation vertically up and down, so that the upper tool table can be adjusted accordingly zgotavlivaemoe molding. Thus, the above advantage of an arbitrarily selectable speed profile of a preferred servomotor can be advantageously and synergistically optimally converted to both large depth feed movements and small and precise alignment movements.

In another preferred embodiment of the thermoforming installation, the second drive device of the upper tool table for actuating the pre-exhaust device has a hydraulic actuator or a crank mechanism driven by an electric servomotor. In both cases, particularly high clock frequencies are achieved. These high clock frequencies can be at least 40, 50 or more clock cycles. In addition, the hydraulic drive of the pre-exhaust devices can advantageously realize the pre-exhaust forces of at least 40 kN with a working stroke of at least 120 mm and a moving mass of at least 200 kg, with a working time of 120 mm is less than 200 ms.

According to another preferred embodiment of the second drive device, it acts on the pre-exhaust device in the upper tool through the push rod, rocker and pressure rod, which is a particularly simple structural solution. In this particularly preferred manner, it is provided that the beam has a displaceable pivoting center, so that its shoulders and the associated force ratios can be matched to this application. The operation of the pre-exhaust devices through the pushing rod, rocker and pressure rod allows the second drive to be located outside the upper tool area, in particular, preferably not directly above it, so when using the hydraulic drive, the outflow of the working fluid is not always completely excluded, since it Preferably, it cannot drain down onto the film web. In addition, it is also preferable that the second drive for the pre-exhaust devices when transmitting its drive forces through the push rod, the beam and the push rod to the pre-exhaust devices can be positioned on the side of the upper tool table so that the second drive will not move with the upper tool table and, therefore, relative to it, so that the second drive exclusively controls the movement of the pre-exhaust devices and, thus, can be especially carefully optimized for high frequencies.

Further, it is preferable that the shift of the center of rotation can be used to set the alternating stroke of the pre-exhaust devices. The offset of the pivot center advantageously ensures a constant stroke of the drive and stepless coordination of the stroke of the pre-exhaust device, so that the top dead center of the pre-exhaust device remains constant and the bottom dead center can be adjusted depending on the height of the molded product.

In a further preferred embodiment of the thermoforming installation, the pre-stretching device can be driven by a second drive device, so that it is possible to make a stroke of at least 120 mm or more in less than 300 ms, preferably in less than 200 ms. Thus, clock frequencies in excess of 60 beats per minute can be advantageously realized, so that for the thermoforming system according to the invention, which for example provides a crank mechanism for a linearly movable lower tool table, in general, high clock frequencies can be achieved, considered so far unrealizable.

The problem in part of the method is solved by the distinguishing features of paragraph 7 of the claims. In this case, for the first time, a method for manufacturing molded products from a polymer film, such as cups, containers, lids, food packaging, etc., using a thermoforming installation, according to the restrictive part of paragraph 1, includes the following steps: a) closing the mold for by moving the movable lower tool table by means of the guiding device, and also actuating it by the drive device, so that it is possible to move the lower tool table about regarding the upper tool table to it; b) the manufacture of molded products in closed form; c) opening the mold by moving the movable lower tool table by means of a guiding device, and also actuating it by means of a drive device with the ability to move the lower tool table relative to the upper tool table from it; d) pushing the molded products, if necessary, into the stacker, and for the first time it is provided that the upper tool table, by means of the first drive device matched with it, is installed in its position relative to the top dead center of the lower tool table in accordance with the correspondingly manufactured molded product, and that the pre-exhaust devices movably mounted in the upper tool can be driven by a second drive device. The related advantages have already been discussed above with respect to the device. Other preferred embodiments of the method are given in the dependent claims.

The invention is explained in more detail below on the options for implementation through the drawings, which depict:

- figure 1: a top view of an embodiment of a thermoforming apparatus according to the invention;

- figure 2: side view presented in figure 1 as an embodiment of a thermoforming installation according to the invention;

- figure 3: an enlarged side view of the drive to rotate the guide assembly shown in figures 1 and 2 of a variant of the thermoforming installation;

- figure 4: section along the line XX from figure 3;

- Fig.5: depicted in Fig.1-4 option in an inclined working position;

6: a schematic simplified view of an exemplary embodiment of a drive according to the invention for driving a pre-exhaust device in a thermoforming unit;

- FIG. 7: a schematic simplified view of an exemplary embodiment that explains how the drive of FIG. 6 can be made;

- Fig. 8: an alternative embodiment of the drive of the preliminary drawing apparatus according to the invention for the thermoforming installation of Figs. 1-5;

- Fig.9: another variant depicted in Fig.6-8 alternative drive options with pre-extraction devices in the initial position;

- figure 10: depicted in figure 9 an embodiment of a drive with pre-extraction devices in the extended position;

- Fig.11: another alternative design of the mechanism with respect to shown in Fig.6-10 versions of the drives of the devices of the preliminary exhaust.

Figure 1 in front view shows an exemplary embodiment of a thermoforming installation 1, according to the invention. The movable nodes of the thermoforming unit 1 are located in the bed 2. The bed 2 can be made in the form of plates of sheet steel, annealed to relieve internal stresses. Located below, i.e. on the floor side, the traverse 4 connects the bed plates 2 and serves simultaneously as a bed for bearings of the crankshaft drive 6. The crankshaft drive 6 is driven in the embodiment shown here from an electric servomotor 8. Its drive force is transmitted through the belt 10 and pulleys 12, 14, which, in particular, is better seen in the side view in figure 2. The crankshaft drive 6 in the embodiment shown here is symmetrically mounted on both sides in the relatively short arms 16 of the lever, and the arms 16 of the lever, in turn, are articulated with a bearing bracket 18 fixed to the crosshead 4.

1 and 2, approximately in the central part, the two-part form 20 of the thermoforming unit of the thermoforming unit 1 is shown in a closed state. Visible in the upper part of FIGS. 1 and 2, the traverse 24 connects both plates 2 of the bed over the two-piece form 20 and serves as the basis of the drive 26 for adjusting the upper tool table 28 with the upper tool 30 fixed on it. Drive 26 for adjusting the upper tool table 28 can be performed, for example, in the form of a precision stroke drive with a thread clearance compensator. The lower tool table 32 carries the lower tool 34 and is positioned by means of the respective linear guides 36 between the rotary guides 38 of the rotary guide assembly 40 (FIGS. 3, 4) of the guide device 42. The pushing cylinders 44 are fixed on the lower side or on the base of the lower tool table 32 upper connecting rod bearings 46.

A chain conveyor 48 is shown between the upper 30 and lower 34 tools of the FIGS. 1 and 2 in the closed state of the mold 20, by means of which the polymer film 50 is fed to the composite mold 20 and, after molding and cutting of products (not shown), the polymer film 50 Using suitably suitable means, they are advantageously bi-directionally flatly stretched in the region of the composite mold 20.

The upper tool table 28 is driven by means of respectively made linear guides 52 between the plates 2 of the bed. The lower tool 34 may have, for example, a screwing surface of 490 × 1040 mm. Thus, it is possible to realize, for example, four rows of eight cavities for 32 molded products with a diameter of about 75 mm. This means the total cutting length of all cut edges 7640 mm, which makes the total cutting force of about 400 kN necessary.

The upper tool 30 is mounted on the upper tool table 28, for example, by means of intermediate elements (not shown). Guides (not shown) facilitate the installation of tools. The thread gap compensator 54 serves to compensate for the gap, for example, for the precision drive 26 of the upper tool table 28. The linear guides 36 for the lower tool table 32 have a clearance-free installation and ensure the exact direction of the lower tool 34. The linear guides 52 of the upper tool table 28 have Slideways mounted free of gaps (not shown).

The actuators 44 for the pushers 56 shown in FIG. 2, located underneath the lower tool table 32, partly in section of the pushers 56 comprise two pneumatic cylinders with a travel stop.

The connecting rod 58 driven by the crankshaft drive 6, which can also be called the connecting rod for the lifting drive of the lower tool table 32, is made in the form of a triangle or Y-shaped shown here. The connecting rod 58 is articulated by the first section 60 with the eccentric section 62 of the crankshaft drive 6. Both the arms 64 of the Y-shaped connecting rod 58 pointing upward in FIGS. 1 and 2 are articulated with the connecting rod bearings 46 of the lower tool table 32. Both of these upper connecting rod bearings 46 are located here with the ability to keep the deflection of the lower tool table 32 and its own weight at the lowest possible level. The Y-rod 58 comprises in the lower portion 60 in the embodiment shown here, preferably only one bearing, so that a crank mechanism is sufficient.

As already mentioned, the crankshaft drive 6 is made with double support rigid bending. In order to facilitate installation, the crankshaft bearings can be separated. The crankshaft drive 6 is installed in the middle on the shoulders 16 of the lever, forming a double balancer. The latter, in turn, is supported by its right side by means of a bearing bracket 18 on the beam 4. The cutting drive 64 acts on the left side of this double balancer. The cutting drive 64 consists, for example, of a hydraulic cylinder and a corresponding hydraulic installation, which creates a sharp cutting course through the hydraulic cylinder, transmitted through a double balancer 16, a crankshaft drive 6, a connecting rod 58, bearings 46 to the lower tool table 32 and, thereby, to the lower tool 34.

The crankshaft drive 6, as already mentioned, may contain as a lifting drive a servomotor 8, which through a gearbox, a gear belt, a gear chain transmission, etc. when executed with a minimum clearance, it acts on the crankshaft drive 6. Closing and opening of the composite form 20 then corresponds to a rotation of the crankshaft by 160 °.

The pivoting arms 38 already shown in FIGS. 1 and 2 for pivoting the lower tool table 32 comprise, in the embodiment shown here, for example, side guides 66 made in the form of cam rollers, shown in more detail in FIG. 3. For example, made in the form of cam rollers, the lateral guides 66 of the pivoting arms 38 move along hardened guides (not shown) and are mounted without gaps for the exact direction of the lower tool 34.

A connecting rod 58 is provided as a drive for rotating the rotary guides 38 of the rotary guide assembly 40 on both sides of the lower tool table 32. A connecting rod turning actuator 68 acting on both guides 38 can be provided as a drive 70 for creating a rotary movement of the lower tool 34 through the rotary guides 38 driven, for example, by a gear servo motor 72 and a synchronizing shaft 74. These details are shown in detail in FIG. 4, showing a section along line XX of FIG. 3.

To limit pivoting movement inward of the frame or bed 2, a stop 76 is provided for the pivot arm, as shown in FIG. 3. This stop 76 for the pivot arm 38 is adjustable to accurately position the lower tool 32.

The drive 84 for regulating the upper tool table 28, which can be made, for example, in the form of a precision drive, serves, for example, not only to control the cutting stroke, but can also be used to turn the cutting stroke on or off. Two spindles 78, barely visible in FIGS. 1 and 2, are driven, for example, via a worm gear 80 on a synchronizing shaft 82 by means of a gear motor 84.

In the embodiment depicted in FIGS. 1-5, two thread clearances made, for example, in the form of bellows pneumatic cylinders of the compensator 54, can pull the upper tool table 28 up through the rods (not shown) in order to eliminate the lateral clearance between the screw and the nut.

As shown in more detail in FIG. 2, a pre-draw unit 86 is provided. The pre-exhaust unit 86 contains, among other things, in the embodiment shown here, a drive 88 made in the form of a servomotor, which through a toothed belt drive (not shown) and a planetary roller-threaded gear, the nut of which is connected by means of disconnect couplings to the pre-exhaust plate 90 and located on it devices 92 preliminary extraction. In this case, the drive of the preliminary exhaust devices may also include a highly dynamic servomotor 88.

In an alternative embodiment (not shown in FIG. 1), the drive of the pre-exhaust unit 86 may include a console 94 that carries a hydraulic cylinder 96 as a drive of the preliminary exhaust devices. The hydraulic cylinder 96 linearly moves with the console 94 relative to the upper tool table 28. The distance between the hydraulic cylinder 96 and the upper tool table 28 remains, thus, always constant. The hydraulic cylinder 96 is enclosed in a casing 98, so that even with minor leaks, the working fluid cannot flow out. The push rod 100 is pivotally connected to the hydraulic cylinder 96, as shown in FIG. 1, and its end facing away from the hydraulic cylinder 96 is pivotally connected to the right end of the rocker arm 102 in the embodiment shown here. The rocker arm 102 is rotatably mounted by means of a bearing support 104. The bearing support 104 acts in this case, through a suitable bearing bracket to the upper tool table 28. A rod 106 is pivotally connected to the left end of the rocker arm 102, which is connected to the plate 90 and the pre-devices 92 located on it body hood. The hydraulic cylinder 96 for driving the pre-exhaust devices 92 may be provided with a servo control that includes a programmable cylinder 96 control device. The necessary hydraulic unit may be located at the base of the machine. The rod 106 can be connected through a compensating sleeve to the plate 90 in the upper tool 30. The casing 98 of the hydraulic cylinder 96 serves not only to detect possible leaks, but can also be servo-controlled and sensors or the like to report possible leaks and have means for their removal . The same applies to hydraulic lines.

As shown in FIG. 2, the thermoforming unit 1 can be matched with a stacker 108 that receives finished molded products after being pushed out of the cavities of the lower tool 34, stacks and retracts them. The stacker 108 may comprise, for example, a comb 110 for removing popped molded products.

To simplify the description, the above reference numerals used when referring to FIGS. 1-5 indicate, in the following discussion of FIGS. 6-11, the same elements or equally or similarly acting parts.

Figure 6 shows a variant of the drive 88 of the preliminary exhaust devices already considered in figure 1-5. The crank mechanism 140 acts through the push rod 100 on the beam 102, which is shown in FIG. 6 for simplicity with a dot-dot line to explain two different positions, namely, the position when the stroke is made and, therefore, when lowering the pre-exhaust devices 92, and reverse stroke i.e. when lifting located on the plate 90 devices 92 pre-exhaust. In this case, the beam 102, which rotates around the rotary center in the bearing support 104, made in the embodiment shown here with the possibility of lateral displacement, as indicated by arrow 142, acts on the rod 106, pivotally connected to the plate 90. Due to the offset 142 of the rotary center 104 of the bearing support across the imaginary horizontal line 144, the stroke 146 can advantageously be varied and the stroke 148 of the drive of the pre-exhaust device can be kept constant. In this case, the downward stroke of the pre-exhaust devices 92 is indicated by arrow 150, and the corresponding return stroke is indicated by arrow 152.

7, in a schematic simplified form, a possible embodiment of the drive 88 of the pre-exhaust device is shown in more detail. The crank mechanism 140 is supported by a bearing 154 on a housing. A gear 156 and a clutch and brake combination 158 connect a crank mechanism 140 to an electric motor 160.

On Fig in a schematic simplified view depicts another alternative embodiment of the actuator 88 of the pre-exhaust device. The design from the point of view of transmission technology, basically, is similar to that considered in Fig.6. Instead of the crank mechanism 140 shown in FIG. 6 in FIG. 8, a hydraulic cylinder 162 is provided, such as, for example, the preliminary exhaust hydraulic cylinder 96 described in FIGS. The offset of the rotary center is also indicated by arrow 142. To offset the rotary center 104 in this view, an electric motor 164 and an adjusting spindle 166 are provided.

Figure 9 schematically shows another embodiment of the actuator 88 of the preliminary exhaust devices. To create efforts, a hydraulic cylinder 96 or 162 is used for preliminary drawing. It is connected at point A with the push rod 100. The push rod 100, in turn, is pivotally connected at point B to the beam 102. The beam 102, in turn, is pivotally connected at point C to the bar 106 of the preliminary exhaust devices. The bar 106, in turn, is pivotally connected at point D to the pre-exhaust plate 90. Pre-exhaust devices 92 are pivotally connected to the plate 90, which, in turn, are mounted in the upper tool 30 with the possibility of linear movement. The upper tool 30 is mounted on the upper tool table 28. The beam 102 is mounted to rotate around point B ₀ in the bearing 104.

In the pre-exhaust device drive 88 shown in FIG. 9, the hydraulic cylinder 96 or 162 is located in front of or behind the upper tool 30, respectively. Alternatively, it is also possible to position the cylinder 96 or 162 next to the tool 30. The pre-exhaust devices 92 are shown in their initial position in FIG. Accordingly, the pre-exhaust devices 92 are shown in FIG. 10 in a schematic view in an extended position. Otherwise, the embodiment of FIG. 10 is similar to that of FIG. 9 of an exemplary embodiment of a drive 88 of pre-exhausters.

11 shows another alternative embodiment of a drive 88 of pre-exhaust devices. It is similar to the embodiment shown in FIGS. 9 and 10, however, it contains an alternative link mechanism. At the same time, longitudinal openings are provided at points B and C of the hinge that allow axial movement of these points of the hinge so that the hydraulic cylinder 96 or 162 can be pivotally connected directly to the beam 102 at point B, so that the push rod 100 can be discarded. however, the rod 106 can be dispensed with if the old points C and D of the articulated joint coincide at a common point C, in which the beam 102, respectively, with a shoulder or support 168 connected directly to the plate 90.

As already mentioned above, for the manufacture of molded products, for example in the form of a cup, the aforementioned heated polymer film 50 by means of preliminary drawing devices 92 installed in the upper tool 30 with the possibility of rectilinear movement is pressed into the forming nests or cavities of the lower tool 34. By creating for example, overpressure in the upper tool 30, the film adheres to the walls of the forming nests or cavities. The pre-exhaust devices 92 then again return to their original position (Fig. 9) in the upper tool 30 (arrows 150 and 152 in Figs. 6 and 8).

To achieve the shortest possible time of manufacturing molded products, a drive 88 with high dynamics pre-stretching devices is proposed. For one cycle of movement of the pre-stretching devices 92 (upward movement 150 and backward movement 152 to the starting position) a duration of at most 300 ms, preferably at most 250 ms, and particularly preferably at most 200 ms, is achieved. In addition, the drive 88 of the pre-exhaust devices discussed in Figs. 6-11 is capable of creating the forces necessary for pre-drawing the polymer film 50. The sum of the forces acting on the individual pre-drawing devices 92 can be up to 50,000 N depending on the form of execution.

In accordance with this, the above-described embodiment of the actuator 88 of the preliminary exhaust devices with the hydraulic cylinder 96 or 162 is provided to create the necessary efforts. The pre-exhaust devices 92 of FIGS. 9-11 are connected via a punch bar 170 to a jumper or plate 90. The punch rods 170 move linearly in the guide bushings 172 of the upper tool 30, so that the entire pre-draw unit 86 can move vertically.

The drive of the pre-exhaust devices 92 is implemented, as already mentioned above, by means of a hydraulic cylinder 96 or 162, which, as shown in FIGS. 1-5, is rigidly connected to the console 94, which, in turn, is located on the upper tool table 28. Linear movement the piston rod 174 is transmitted by means of a connecting or pushing rod 100 with the help of the swivel hinges A and B first to the beam 102. The beam 102, as mentioned above, is supported at point B ₀ with the possibility of rotation relative to the upper tool table 28. Connecting the second rod or rod 106 of the preliminary exhaust devices with swivel joints C and D finally transfers the movement of the rocker arm 102 to the preliminary exhaust unit 86.

Shown schematically in FIGS. 6-11, transmission 88 may vary in a variety of ways. In an exemplary embodiment, the movement of the rocker arm 102 is transmitted to the pre-stretching unit 86 through a finger or the rocker. Similarly, cylinder 96 or 162, as an alternative to rigidly connecting to console 94, can only be pivotally connected to console 94 and thereby be rotatably held.

Another advantage of the hydraulic drive 88 of the pre-exhaust devices is the high forces it creates with very good dynamics. There is no danger of thermal overload.

The present invention thus provides, for the first time, in a preferred manner, a thermoforming apparatus for manufacturing molded articles from a polymer film, such as cups, containers, lids, food packaging and the like, with a two-piece thermoforming unit. The form consisting of two parts contains a fixable upper tool table with an upper tool with movable preliminary extraction devices and a movable lower tool table with a lower tool with cavities. The movable lower tool table is guided by a guiding device and has the ability to move due to the drive device relative to the upper tool table to and from it. In this case, the upper tool table for the first time contains, according to the invention, the first drive device matched with it for mounting the upper tool table in its position relative to the top dead center of the lower tool table in accordance with the correspondingly manufactured molded product. Further, the upper tool table for the first time contains a second drive device that is matched with it to drive pre-exhaust devices movably mounted in the upper tool. In addition, the present invention for the first time offers an economical method of manufacturing molded products from a polymer film.

Since a hydraulic actuator is proposed for pre-exhaust devices, it can preferably be provided with a servo control as a so-called linear amplifier, so that its course and speed profile can be controlled and thereby set them independently.

Using a thermoforming machine according to the invention, it is possible to process polymer films of PP (polypropylene), PS (polystyrene), PE (polyethylene), PET (polyethylene terephthalate), ABS (acrylonitrile butadiene styrene) or PVC (polyvinyl chloride). The polymer film supplied to the thermoforming machine in the form of a web may have a width of at least 250-750 mm and a thickness of at least 0.3-4 mm. The forming surface between the upper and lower tools is at least 700 × 450 mm. The maximum closing force is at least 400 kN with a maximum cutting length of at least 8400 mm.

List of Reference Items

1 - thermoforming installation

2 - bed or frame

4 - lower traverse

6 - crankshaft drive

8 - electric servomotor

10 - belt

12 - pulley

14 - pulley

16 - lever arm

18 - bearing bracket

20 - two-part form

24 - upper traverse

26 - drive upper tool

28 - upper tool table

30 - upper tool

32 - bottom tool table

34 - bottom tool

36 - linear guide of the lower tool table

38 - rotary guides

40 - guide assembly

42 - guide device

44 - drive pusher

46 - connecting rod bearing

48 - chain conveyor

50 - polymer film

52 - linear guide upper tool table

54 - compensator for clearance of threads

56 - pusher

58 - connecting rod

60 - the first section of the connecting rod

62 - eccentric shaft section

64 - punch drive

66 - lateral guide of the rotary lever

68 - connecting rod rotation drive

70 - rotation drive

72 - gear servo

74 - synchronizing shaft

76 - emphasis of the rotary lever

78 - lead screw

80 - worm gear

82 - synchronizing shaft

84 - gear motor

86 - block preliminary extraction

88 - pre-exhaust device drive

90 - pre-exhaust plate

92 - pre-exhaust devices

94 - console for the drive of pre-exhaust devices

96 - pre-exhaust hydraulic cylinder

98 - casing

100 - push rod

102 - rocker

104 - bearing support rocker

106 - pre-exhaust bar

108 - stacker

110 - comb

140 - crank mechanism

142 - displacement of the rotary center

144 - imaginary horizontal line

146 - variable stroke

148 - constant stroke

150 - working stroke

152 - reverse

154 - bearing

156 - transmission

158 - combination of clutch and brake

160 - electric motor

162 - hydraulic cylinder

164 - electric motor

166 - adjusting spindle

168 - shoulder or support

170 - punch bar pre-exhaust devices

172 - rocker guide

174 - piston rod

Claims (9)

1. Thermoforming installation (1) for the manufacture of molded products from a polymer film (50) with a two-part form (20) thermoforming unit, and the two-part form (20) contains a lockable, adjustable upper tool table (28) with an upper tool (30) with pre-drawn devices (92) movably mounted in it and a movable lower tool table (32) with a lower tool (34) with cavities, the movable lower tool table (32) being guided by guide device (42) and is configured to move due to the first drive device relative to the upper tool table (28) to and from it, characterized in that the upper tool table (28) contains the first drive device (26) matched with it the upper tool table (28) in its position relative to the top dead center of the lower tool table (32) in accordance with the correspondingly manufactured molded product, while the upper tool table (28) with holds a second drive device (88) matched with it for driving pre-exhaust devices (92) movably mounted in the upper tool (30), the lower tool table (32) together with its first drive device being made with the possibility of vertical movement within a straight guide this the lower tool table of the guiding device by means of the second drive device of the lower tool table for the implementation of the course of cutting. 2. Installation according to claim 1, characterized in that the first drive device (26) for installing the upper tool table (28) is an electric servomotor (84). 3. Installation according to claim 1 or 2, characterized in that the first drive device (26) through a synchronizing shaft (82) with worms / wheels mounted on it interacts with two adjusting spindles (78), which, in turn, act on the upper tool table (28) with the possibility of its vertical movement up and down in its horizontal orientation so that the upper tool table (28) is made with the possibility of adjustment to suitably manufactured molded product. 4. Installation according to claim 1, characterized in that the second drive device (88) of the upper tool table (28) for driving the pre-exhaust devices (92) has a hydraulic drive (96, 162) or a crank mechanism driven by an electric servomotor (160) (140). 5. Installation according to claim 1, characterized in that the second drive device (88) through the pushing rod (100), rocker (102) and push rod (106) acts on the device (92) pre-exhaust in the upper tool (30), advantageously by means of a biasable rotary center B _{0 of the} rocker arm (142). 6. Installation according to claim 1, characterized in that the preliminary drawing device (92) is arranged to be actuated by the second drive device (88) so that it has the possibility of making a stroke (146) of at least 120 mm in less than 300 ms, mainly in less than 200 ms. 7. Installation according to claim 1, characterized in that the molded products from a polymer film (50) are cups, containers, lids, food packaging. 8. A method of manufacturing molded products from a polymer film on a thermoforming installation (1) according to claim 1, which includes the following steps: closing the mold (20) due to the direction of the movable lower tool table (32) by means of a guiding device (42), and bringing it into action by the first drive device so that the lower tool table (32) moves relative to the upper tool table (28) to it, the manufacture of molded products in a closed form (20), and movably installed in the upper tool (30) of the pre-exhaust device (92) is driven by a second drive device (88) of the upper tool table, and the lower tool table (32) with its first drive device is raised within the direct guide line of this lower tool table of the guide device by the second drive devices of the lower tool table for the implementation of the course of cutting, and again lower, opening the form (20) due to the direction of the movable lower tool stand a (32) by means of a guiding device (42), as well as actuating it by means of a drive device, so that it is possible to move the lower tool table (32) relative to the upper tool table (28) from it, pushing the molded products, if necessary, a stacker, and the upper tool table (28) by means of the first drive device (26) matched with it is adjusted in its position relative to the top dead center of the lower tool table (32) in accordance with correspondingly manufactured molded product. 9. The method according to claim 8, characterized in that the molded products made of a polymer film (50) are cups, containers, lids, food packaging.

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