GB2312395A

GB2312395A - Device for effecting displacement of tool support in press apparatus

Info

Publication number: GB2312395A
Application number: GB9707864A
Authority: GB
Inventors: Dominique Schwab
Original assignee: Erca SA
Current assignee: Erca SA
Priority date: 1996-04-24
Filing date: 1997-04-18
Publication date: 1997-10-29
Anticipated expiration: 2017-04-18
Also published as: ES2150330B1; ES2150330A1; FR2747958A1; DE19711759C2; GB9707864D0; FR2747958B1; GB2312395B; DE19711759A1

Description

2312395 TITLE Press Apparatus This invention relates to a press apparatus

comprising a lower support for a lower tool, an upper support for an upper toot situated above the lower support and means for the vertical displacement of the lower support, designed to cause this support to perform an intermittent movement in the course of which it is capable of occupying an upper position in which the lower tool can engage with the upper tool in order to grip material between the said tools, and a lower position in which the lower tool is moved away from the upper tooVin order to enable the material to be released from the space between the said tools, the apparatus including means for guiding the vertical movement of the lower support.

An apparatus of this type is currently used, for example, in an installation for manufacturing receptacles from a band of thermoplastics material. An installation of this kind comprises a number of stations situated in succession to one another in the direction of motion of the said band. In at least a certain number of these stations the thermoplastic band across the partly formed receptacles are held between a lower tool and an upper tool. This is the case, for example, in the thermoforming station, in which the lower tool consists of a mould block having open cavities while the upper tool comprises the mould cover and 2.5 thermoforming punches which, when the band is held between the upper 41674.spe 2 edge of the mould block and the lower edge of the cover, penetrate the cavities in order to cause the thermoplastic band to fit around their contours. It will be understood that when a band part to be thermoformed is present in the thermoforming station, the mould block has to be placed in the upper position to hold the band against the mould cover, and that once the thermoforming process has been completed this lower part must be enabled to descend to a sufficient distance to move away from the path of the thermo-formed receptacles and enable the band to continue on its way.

Other stations, such as one designed for sealing the covers onto the edges of containers, may likewise involve the use of a press mechanism. In this case the upper tool may consist of a heat sealing tool while the lower tool may be a simple counterthrust device for the upper tool.

In the known apparatus of this type the means for the vertical movement of the lower support comprise two transversal shafts positioned underneath this support and driving four cams in rotation. Rollers integral with the lower part of the support interact with the cams. It can be seen that the bottom support can be raised or lowered according to the rotation angle of the cams.

A mechanism of this type suffers from a number of drawbacks. In the first place, the rotation of the two transversal shafts driving the cams obviously has to be synchronised, so that a connecting gear between the said shafts is required. The mechanism is thus relatively complicated and takes a long time to assemble or dismantle for maintenance 3 purposes, with the consequent effects on output.

The maximum force obtainable with this type of press is limited by the characteristics of the rollers. The addition of a third transversal shaft fitted with new rotary cams or the addition of further rotary cams to the existing two shafts accompanied by an appropriate number of rollers, in an attempt to distribute the stresses, does not provide a satisfactory solution. The fact is that such solutions render the mechanism still more complicated. The addition of further cams to the two shafts would subject these latter to excessive stresses. The addition of a third shaft with further rotary cams would necessitate the addition of a further gear train in order to render the third shaft fast in rotation with the other two. The number of mechanical lifting devices of which the position in relation to one another would have to be very accurately adjusted would then become too great to be compatible with the requirements of series production, while the assembly and dismantling times involved in their maintenance (the latter being frequent in consequence of the premature wear suffered as a result of the high frictional forces occurring) would become unacceptable.

An object of this invention is to remedy these drawbacks by provision of simpler means for the vertical movement of the lower support than those of the prior art, comprising a smaller number of parts or at least parts of which the positions in relation to one another are very easy to adjust, so that the assembly and dismantling involved in any necessary

1 maintenance operation will be considerably simplified. A further object of this invention is to provide a mechanism which will prove compatible with 4 the treatment, particularly in the thermoforming station, of thermoplastic bands of considerable width. According to this invention there is provided press apparatus comprising a lower support for a lower tool, an upper support for an upper tool situated above the lower support and means for the vertical displacement of the lower support, whereby said support performs an intermittent movement during the course of which said support may occupy an upper position in which the lower toot can interact with the upper tool in order to grip material between the said tools and a lower position in which the lower tool is moved away from the upper tool in order to enable the material to be released from the space situated between the said tools, the apparatus including means for guiding the vertical movement of the lower support, the means for the vertical displacement of the lower support comprising:

a) a vertically fixed base having at least one fixed cam surface having a peak region and a valley region, b) at least one operating rod with a first end fitted with a roller capable of interacting with the said cam surface and a second end connected to the lower support through a free pivot connection, and c) a control rod having a first end connected to the operating rod in the region of the first end of this latter through a free pivot connection as well as a second end connected through a free pivot connection to driving means capable of causing the said second end of the control rod to effect a movement corresponding to at least one part of a substantially circular curve.

Thanks to this formation the assembly and dismantling operations are greatly simplified and all that is necessary for this purpose is to keep the lower support in a position rendering the rods accessible and to disconnect the operating rod from the control rod. The mechanism of the rods can thus be dismantled with the greatest of ease, so that the parts can be taken to the workshop for any necessary adjustments. The shutdown time can be kept very short by installing a spare set of parts during this adjustment process.

By way of contrast, the complex rotary parts of the known type of apparatus are difficult to dismantle, so that any adjustments or regulating operations often have to be carried out on the actual production site, causing the entire installation to be shut off while they are being effected.

Even if the operating rod is situated under the lower support as is generally the case of the present invention, the dismantling operation is still easy, owing to the simple nature of this part and the connection with the control rod.

It should also be noted that the surface of the cam is fixed, so that it is easier to give this part dimensions which will enable it to resist wear, which was difficult to achieve with the rotary cams of the prior art, as they had to be compatible with the process of driving these cams in rotation. The fact is that for most maintenance operations the base presenting the fixed cam surface does not have to be removed. The only rotating part really subject to wear is the roller interacting with the said cam surface. As previously stated, this roller is integral with the operating rods, which is

6 itself easy to remove.

In one advantageous embodiment of this invention the base presents at least two similar cam surfaces arranged in such a way as to form at least one pair of cam surfaces situated opposite each other. In this same version the apparatus comprises at least one first pair of operating rods associated with the said first pair of cam surfaces, the end of each rod of the first pair being fitted with a roller capable of interaction with one of the cam surfaces of the first pair of cam surfaces and the first ends of the rods of the first pair being connected by a first horizontal coupling shaft extending between the two cam surfaces. The first end of the control rod is then connected to the said first coupling shaft.

In this version the movements of the two control rods are synchronised very simply thanks to the horizontal coupling shaft connecting their first ends. This arrangement will be adopted, for example, for the thermoforming station of an installation processing a thermoplastic band of a width of the order of 320mm.

In one particularly advantageous version of this invention the apparatus includes at least one supplementary module of rods comprising a connecting rod, a second pair of operating rods similar to the operating rods of the first pair and a second horizontal coupling shaft connecting the first ends of the operating rods of the second pair, and also at least one supplementary module of cams comprising a second pair of cam surfaces situated opposite each other, the cam surfaces of the second pair being analogous to those of the first pair and offset in relation to these latter. The connecting rod is connected by its first end to the second coupling 7 shaft and by its second end to the first coupling shaft.

It will be understood that to lift heavier mould blocks, for example in a thermoforming station of a useful width of wider than 480mm, it is sufficient to plan for the supplementary rod module. The movement of the supplementary operating rods is easily synchronised with that of the operating rods of the first pair, due to the connecting rod. The operating rods of the second pair are synchronised with one another due to the second coupling shaft. This a simple system enabling the stresses arising to be satisfactorily distributed in order to avoid premature wear on the parts.

If the lifting forces applied are increased still further, for example in order to process thermoplastic bands of a useful width of 600 or even 825mm, a further supplementary rod module can be added. This module comprises a connecting rod and a third pair of operating rods. These latter are coupled to the third horizontal coupling shaft, to which is connected the first end of the connecting rod. As regards the second end of this rod, it can be connected to the aforementioned second coupling shaft in order to synchronise the rods of the third pair with those of the second pair. To interact with the operating rods of the third pair, a third pair of cam surfaces, offset in relation to those of the second pair, must be provided.

It has already been pointed out that the invention makes R possible, in particular, to assemble and dismantle the means for the vertical movement of the lower support. Again with a view to simplifying the maintenance operations and ensuring that the time occupied by them 8 is compatible with the high production rates required, the invention is also aimed at a simplification of the assembly and dismantling of the upper tool supported by the upper support.

For this purpose the upper support of the apparatus comprises means forming slides in relation to which the upper tool is able to slide at a substantially horizontal plane in order to be placed in position in the press apparatus and extracted therefrom and also means for clamping the upper tool in relation to the said means forming slides, in order to clamp the said tool in the operating position.

Thanks to these arrangements the operation of positioning the upper tool in the press mechanism is simplified as all that is required is to slide it into the means forming a slide and fix them in position therein. It is not necessary to resort to any complicated securing means on the upper support. Furthermore, in spite of the weight (which may be considerable) of the upper tool and any of the elements attached thereto, no lifting devices or temporary positioning equipment has to be used during the assembly phase. The fact is that from the moment when the upper tool is first inserted in the slides it is adequately supported in the vertical direction, and all that is required is to move it into its operating position and secure it therein.

In one particularly advantageous embodiment the upper support comprises two parallel side rails and a frame to which the upper tool can be affixed, this frame being equipped with projecting side elements capable of interacting with the rails in order to slide in these latter.

The invention will be more clearly understood and advantages will 9 become apparent from a study of the detailed description which now follows relating to embodiments shown in the drawings as examples.

The description refers to the accompanying drawings, wherein:

Figure 1 shows a part cut-away view in perspective of the press mechanism equipped with means for the vertical movement of the lower support and according to one advantageous arrangement, Figure 2 shows a view in perspective, of part of the means for the vertical movement, Figure 3 is an underside view of Figure 2 with the driving means for the second end of the control rod being illustrated schematically with certain elements being shown in section for reasons of clarity, Figure 4 is a section along IV of Figure 1 (see also Figure 5), certain elements being shown in section in the plane 1 V and other elements illustrated schematically as an external view in the direction D, for purposes of simplification, and Figure 5 is a view along the line V-V of Figure 4, certain elements being shown in section and others as an external view, again for the purposes of simplification.

The press apparatus shown in Figure 1 comprises a lower support 10, formed for example by a horizontal plate, supporting a lower tool 12, consisting for example of the mould block of a thermoforming station.

The apparatus includes an upper support identified by the general reference number 14, situated above the lower support 10 and supporting an upper tool 16, comprising for example a thermoforming mould cover and thermoforming pistons.

The press apparatus may be situated in the thermoforming station of an installation for the manufacture of receptacles from the thermoplastic band. This latter is fed forward step by step in the direction F and passes between the lower tool 12 and the upper tool 16. Throughout the rest of the description it will be assumed that the plane in which the band is fed into the press apparatus is horizontal, as is usually the case.

The thermoplastic band or more generally a material to be processed must be gripped between the lower tool 12 and the upper tool 16 so that they can act on it.

The thermoplastic band is illustrated schematically in broken dotand-dash lines in Figures 4 and 5, before thermoforming in Figure 4 and after thermoforming in Figure 5. In these diagrams the reference N1 denotes as a whole the level of the feed plane of the band.

This level N1 is likewise shown in Figure 1 and corresponds on the whole to the position occupied by the upper edge of the mould block 12 in its position and the lower edge of the mould cover 16 when the thermoplastic band is gripped between these two elements. The mould block 12 is illustrated in Figure 1 in its low position, and the distance d indicates the amplitude of the displacement between the upper and lower positions of the mould block and of the lower support 10. Thisamplitude 11 d corresponds substantially to the length of the operating rod or rods between the two shafts situated near their ends.

It may be seen that the level N1 is also situated very slightly below the level occupied by the lower edge of the mould cover 16 in Figure 1. The fact is that, as will be explained hereinafter, this cover may itself be subjected to a very slight vertical displacement in such a way as to avoid friction against the upper face of the thermoplastic band when it is fed into the station. The displacement d must be at least equal to the height of the cavities provided in the mould block, in order to ensure that the thermoplastic band will advance freely after the thermoforming.

Needless to say, the intermittent vertical movement of the lower support must be synchronised with the step-by-step feed movement of the thermoplastic band in the station.

The apparatus comprises means for guiding the vertical displacement of the lower support 10.

More precisely, in the example illustrated, the upper support 14 is connected to a stand 10 via vertical uprights 22 on which the support 14 is mounted. In the course of its vertical displacement the lower support 10 slides in relation to these uprights, which then function as guides. For this purpose the support 10 is provided, at certain points corresponding to the position of the uprights 22, with apertures 24 through which the said uprights pass.

The uprights 22 can take the form of jacks by means of which the upper tool is caused to perform the slight vertical displacement required to move it to the level N1.

12 For this purpose the uprights 22 comprise hollow tubes 22a functioning as cylinders, which are penetrated by the piston rods 22b. It is in relation to the fixed hollow tubes 22a that the lower support 10 effects its sliding movement. Where the upper support 14 is concerned, it is mounted on the upper ends of the piston tubes 22b.

A description will now be given of the means for the vertical displacement of the lower support, by reference to Figures 1 to 3. They will be particularly clear from the opened-up lower part of Figure 1.

These means comprise a base 26 which is fixed and present at least one fixed cam surface 28. This cam surface has an extreme high region (peak) 28a and an extreme low region (valley) 28b. They also comprise a control rod 30 and at least one operating rod 32. This latter has a first end 32a fitted with a roller 34 capable of interacting with the cam surface 28 and a second end 32b connected to the lower support 10 via a freely pivoting connection.

By freely pivoting connection is meant a connection in which the two interconnected elements are capable of rotating freely in relation to each other about the geometrical axis of the connection. For example, the second end 32b of the rod can be provided with a connecting pivot 36 mounted in such a way as to pivot freely in relation thereto. This pivot is connected to a connection plate 38 integral with the lower face of the lower support 10. To enable the pivot 36 to rotate in relation to the end 32b of the operating rod, a bearing such as a ball bearing can be provided for this pivot inside the orifice made in the end 32b of the rod in which the pivot is inserted.

13 In an analogous manner the roller 34 is mounted in such a way as to rotate freely in relation to the first end 32a of the operating rod 32. An example of this method of assembly will be described in due course by reference to Figure 3.

The control rod 20 has a first end 30a connected to the operating rod 32 in the region of the first end 32a of this latter via a freely pivoting connection. The send end 30b of this rod 30 is connected, likewise via a freely pivoting connection, to driving means desired to subject it to a displacement according to at least one portion of a substantially circular curve.

These driving means are shown schematically in Figure 3. They comprise a motor such as a servo-motor (represented as a whole by the block 40) having an output shaft 42. They also include a transmission element 44 fast in rotation with the output shaft 42 and connected to the second end 30b of the control rod by a connecting shaft 46. This shaft 46 is eccentric in relation to the output shaft of the motor, i.e. parallel with this shaft and at a distance therefrom. The transmission element 44 has in fact the general shape of a crank or disc crank. The connecting shaft 46 is mounted in such a way as to rotate freely about its geometrical axis 47, either in relation to the transmission element 44, in relation to the second end 30b of the rod or in relation to both these elements. In the example illustrated the second end 30b of the control rod is provided with a boring 31 penetrated by the connecting shaft 46. A bearing 48, such as a ball bearing, is provided inside the boring 31, to interact with the connection shaft 46. On the other hand, this latter may be fixed in relation to the transmission element 44. As indicated previously, it is also possible to consider the converse configuration or provide a roller bearing for each of the two ends of the shaft 46.

The curve described by the coupling shaft 46, which obviously corresponds to that described by the second end 30b of the rod 30, goes from a first to a second extreme point.

The first extreme point corresponds to the position shown in Figure 3, for which the distance between the pivot 46 and the end of the cam surface furthest therefrom is at its minimum and is approximately equal to the length L30 of the rod 30 (length measured between the connecting zones between the rod and the shaft 46 and the rod 42). The second extreme point corresponds to the position shown in Figure 2, for which the distance between the shaft 46 and the same end zone of the cam surface is at its maximum. For this second extreme point, the distance between the shaft 46 and the end zone of the cam surface nearest to the said shaft is approximately equal to the length 1-30.

For the passage from one extreme point to the other the shaft 46 describes at least one part of a substantially circular curve. The output shaft 42 of the motor may, in fact, oscillate and turn by an angle of 1800, for example, in one direction of rotation and then in the opposite direction. this shaft may likewise describe complete rotations, in which case the two extreme positions of the shaft 46 correspond to two diametrically opposite positions.

As may be seen from the diagrams, the upper extreme region 28a of the cam surface advantageously corresponds to a flat zone on which the roller 3 may rest in order to keep the support 10 in the upper position. The period for the ascent of the ramp of the cam surface between its low extreme position and its high extreme position advantageously corresponds to a traction period of the rod 30, i.e. to a passage of the shaft 46 from the position shown in Figure 3 to its other extreme position. It is during this ascent phase that the stresses involved may be at their maximum, particularly from the point of view of the friction. In order to limit the latter the movement of the shaft 46 is advantageously regulated in such a manner that the rod 30 assumes a position substantially parallel to the ramp of the cam surface during this ascent phase.

As may be seen from Figures 1 to 3, the means for the vertical movement of the support advantageously comprise a number of cam surfaces and a number of operating rods. These means may in fact be regarded as presenting a modular structure. The head module consists of the aforementioned control rod and of two operating rods. More precisely, for this head module, the base 26 presents two analogous cam surfaces 28 and 29 situated opposite each other and a certain distance apart. They thus constitute a pair of parallel cam surfaces. The apparatus thus comprises a first pair of operating rods consisting of the rod 32 and a rod 33 associated therewith. The rod 33 is similar to the rod 32, particularly in that it is of the same length. The first end of the rod 33 is fitted with a roller 34 analogous to that with which the first end 32a of the rod 32 is equipped. This roller interacts with the second cam surface 29.

For purposes of simplification it is only the first ends 32a and 33a 16 of the operating rods 32 and 33 that are shown in section in Figure 3. It may be seen that the first ends of the rods 32 and 33 of the first pair are interconnected by a horizontal coupling shaft 52, hereinafter called the "first coupling shaft'. The shaft 52 extends in the space provided between the two cam surfaces 28 and 29. To control the movement of the two operating rods 32 and 34 simultaneously and synchronise them, the first end 30a of the control rod 30 is directly connected to the first coupling shaft 52. The apparatus may be assembled in such a manner that the rollers 34, the two operating rods 32 and 33 and the control rod 30 are all free to rotate in relation to the shaft 52. For this purpose it is sufficient, for example, to use roller bearings in each of the connections between the shaft 52 and the various elements aforementioned. The method may equally well be adopted, for example, of making the rods 32 and 34 fast in rotation with the shaft 52 while the rollers 34 and the control rod 30 are mounted so that they can rotate freely in relation to the said shaft. Whatever the method of assembly selected it should be such that at least the control rod or the operation rods are free to rotate in respect of the shaft and that the rollers 34 are likewise free to rotate.

It will be noticed that the cam surfaces constitute the lower faces of slits 27 made in vertical wall elements 16a, and 26b. The pair of parallel cam surfaces 28 and 29 is obtained by placing the two wall elements parallel to each other. The construction based on slits provides a means of ensuring that the rollers will remain in contact with the cam surfaces.

As indicated by way of introduction, a press apparatus equipped solely with this head module may be used for example in the

17 thermoforming station of an installation which processes thermoplastic bands of a width of the order of 320 mm. The apparatus shown in the diagrams, however, includes a supplementary module of rods comprising a connecting rod 56 and a second pair of operating rods marked 58 and 59 respectively. The first ends of these rods, 58a and 59a respectively, are interconnected by a coupling shaft 60, hereinafter termed the "second coupling shaff'.

A supplementary module of cams is provided to interact with the operating rods of the supplementary module of rods. It comprises a second pair of cam surfaces, 62 and 63 respectively, situated opposite each other. The cam surfaces of the second pair are analogous to those of the first pair and offset in relation to these latter. The connecting rod 56 is connected by its first end 56a to the second coupling shaft 60 and by its second end 56b to the first coupling shaft 52. This connecting rod 56 is aligned with the control rod 30. The supplementary rod module and the supplementary cam module are advantageously situated behind the head module. More specifically, they are situated beyond the control rod 30 as viewed in the direction from its second end 30b towards its first end 30a. The cam surfaces 62 and 63 are advantageously situated in the prolongation of the cam surfaces 28 and 29 and are separated from these latter by dividing portions 66. They may be provided in the same vertical wall elements 26a and 26b or in other parallel wall elements.

Means for vertical displacement, comprising the head module and supplementary module, are suitable for the use of a press apparatus in the thermoforming station of a plant in which a thermoplastic band of a 18 useful width of 480mm is treated.

If it is desired to treat a thermoplastic band of a greater effective width, for example 600 or 825mm, all that is required is to add a further supplementary module, its actual connecting rod being connected to the second coupling shaft 60. The head module may thus be succeeded by two or even three supplementary modules situated in succession to one another.

It is possible, for instance, to provide a second supplementary module of rods, comprising a connecting rod, a third pair of operating rodsanalogous to the operating rods of the first and second pairs, and a third horizontal coupling shaft interconnecting the first ends of the operating rods of the third pair, as well as a second supplementary cam module comprising a third pair of cam surfaces situated opposite each other, the cam surfaces of the third pair being analogous to those of the first and second pairs and offset in relation to these latter. The offset between the third and the second cam surfaces is preferably analogous to the offset between the second and the first pair, the second pair being situated between the first and the third. The connecting rod of the second supplementary rod module is then connected by its first end to the third coupling shaft and by its second end to the second first coupling shaft.

In Figure 3 it may be seen that the first end 30a of the control rod is fork-shaped, i.e. has a U-shaped profile. The two parts forming the branches of the U, 31 a and 31 b respectively, are a certain distance apart, a sufficient space being left between them to accommodate the second end 56b of the connecting rod 56. The parts 31a and 31b present 19 orifices large enough to enable the shaft 52 to pass between them. These orifices may be fitted with bearings for the said shaft. When the rod 56 is in position the various orifices can thus be aligned with one another and accommodate the shaft 52.

A converse design would be feasible in which the second end 56b of the rod 56 has a U-shaped profile in which the first end 30a of the control rod 30 would be inserted.

The connecting rod 56 has a similar configuration to the control rod 30 except that it is not necessarily the same length. The first end 56a may thus be U-shaped in such a way as to accommodate the second end of the connecting rod of a further supplementary module following the first.

A description will now be given of Figures 4 and 5, showing the upper part of the press apparatus. This illustrates the ends of the upper parts 22b of the uprights 22, which bear the upper support 14. The supporting crosspieces 70 and 72 are directly connected to these parts 22b of the uprights and combine with them to form a support frame for the various elements integral with the upper tool 16.

This tool comprises a cover 74 for the mould block 12 of the thermoforming station. This cover includes a side wall 74a and an upper plate 74b. This plate is itself situated underneath another plate 76 and supported by this latter. The plate 74b can nevertheless move vertically in relation to the support plate 76. For this purpose these two plates are interconnected by jacks, the jack 78 being visible in the opened-up part of Figure 5. As regards the plate 76, this is directly supported by the frame and, to be more specific, by the crosspieces 70 and 72.

In addition to the mould cover 74 the upper tool 16 comprises an assembly of pistons 78 in which the number of pistons 78a corresponds to the number of mould cavities 12a in the mould block. Once the two parts of the mould have closed on the thermoplastic band 18 the pistons must be capable of moving in order to penetrate the cavities 12a. For this purpose, the assembly of pistons 78 is connected to the support plate 76 by connection means enabling it to move vertically in respect of this latter. The pistons are thus able not only to accompany the vertical movement of the mould cover in respect of the plate 76 but also to move in respect of the said cover in order to penetrate the cavities of the mould. The means for the vertical displacement of the pistons comprise a motor 80 mounted on the support plate 76. The output shaft 81 of this motor drives a parallel driving shaft via a transmission belt 84. The displacement of the assembly of pistons 78 is effected via a ball screw. More precisely, the external periphery of the driving shaft 82 presents a spiral surface 83 (grooving or ribbing). The assembly of piston 78 is supported by a frame 86 of which a central part 88 has an aperture in which the shaft 82 engages. A rolling system interacting with spiral 83 is provided in the said aperture. In addition to its central part 88 the frame 86 is provided with uprights 90 which pass through the plates 76 and 74 and are connected to the upper part 79 of the piston assembly 78. It will be evident that when the shaft 82 is caused to rotate the central part 88 of the frame 86 slides in relation to the said shaft, resulting in the displacement of the frame 86 and of the piston assembly 78 connected 21 thereto. A first direction of rotation of the shaft corresponds to the descent and a second direction to the ascent.

When the thermoplastic band 18 enters the press apparatus the latter must be open, i.e. the two tools 12 and 16 are at a certain distance apart. At the end of the band feed movement the lower support 10 is moved into the upper position in order to bring the upper edge of the mould block 12 to the level N1, while the rods of the piston 22b can descend slightly in the cylinders 22a of the uprights so that the whole of the upper support can likewise descend slightly until it has moved the lower edge 74' of the mould cover 74 to the level N1, causing the band 18 to be gripped between the two mould parts.

Once this position has been reached the cylinder or cylinder 78 between the support plates 76 and 74b have descended to the point where they press the cover 74 of the mould tightly against the mould block. The motor 80 is then actuated in order to cause the thermoforming pistons to descend in the cavities of the mould block 12. Once the pistons 78a have performed their function the motor 80 can be actuated in the reverse direction in order to allow the assembly of pistons 78 to re-ascend, causing the pistons 78a to emerge from the cavities 12.

Simultaneously with this operation or very shortly afterwards, the means for vertical displacement of the lower support 10 are actuated in order to cause the mould block 12 to descend to its bottom position, and the piston 78, as well as the piston rods 22b, re-ascend and move the lower edge of the upper tool away from the upper face of the thermoplastic band 18.

22 It will be understood that the upper tool is a complex assembly which may have to be installed or dismantled for maintenance purposes or replaced by a similar upper tool. To enable the upper tool to be assembled and dismantled without loss of time the upper support 14 comprises means forming a slide, in relation to which the entire upper tool can slide in a mainly horizontal direction. These means forming a slide are preferably transversal to the feed direction F of the band, so that the upper tool can be disengaged from the side of the installation.

As in the example shown the means forming a slide preferably comprises two parallel side rails, marked 92 and 94 respectively. These rails are integral with the crosspieces 70 and 72. Their profile is advantageously U-shaped, with the opening part on the inside of the press apparatus, i.e. each one towards the median plane IV.

The upper support 14 includes the frame 93 on which the entire upper tool can be mounted. More precisely, it is to the support plate 76 that the various tools constituting the upper tool are affixed, as has already been made clear, the said plate being itself integral with the frame 93. As may be seen from Figure 5, this frame is fitted with projecting side elements 96 capable of interacting with the rails 92 and 94 in order to slide in these latter.

In order to limit the friction, projecting side elements will include roller bearings.

Means for securing the upper tool in relation to the means forming a slide will advantageously comprise stops connected to the side rails and capable of interacting with the projecting side elements of the frame, e. g.

23 formed by the rollers 96. These stops, for example, may comprise stops 100 which are shown schematically by a dot-and-dash line in Figure 4 and which are positioned in the rails and which are contacted by the rollers furthest away from the extraction face by which the upper tool is extracted from the support 14. These stops may be fixed. On the other side (that of the tool extraction face) securing means may comprise movable stops 102, likewise shown schematically in dot-and-dash lines, which may be at least partly moved aside in order to release the traject for the rollers 96 in the rails 92 or 94 and be returned to the active blocking position, shown in Figures 4 and 5, in order to prevent the displacement of these rollers.

It would also be possible to provide, on the extraction face side, retractable pins capable of interacting directly with the rollers 96 or, more precisely, with their rotation shafts, in order to block the movable assembly formed by the various parts of the upper tool and by the frame and adjust the position of this assembly accurately.

As may be seen from Figures 1 to 4, to enable the upper tool to be extracted from the apparatus, the latter is advantageously provided with extension rails 104 which can be positioned in the continuation of the open free ends of the rails 92 and 94, prolonging these latter by a length such that the frame 93 can slide in these extension rails (via the rollers 96) at least as far as a position in which the upper tool 16 is totally offset in relation to the lower support 10, so that it can be extracted in its entirely and moved by a mobile device. The rails 104, for example, may be provisionally affixed to the crosspiece 70 and 72 by screw-type or similar securing systems. The inner ends 104a of the rails 104 can engage the 24 open free ends of the crosspieces in which the rails 92 and 94 are positioned in order to reach the free ends of these rails. The respective positions of the inner end 104a of the rail 104 and the free end 92a of the rail 92 can thus be seen in Figure 4. The side rails and the extension rails thus form continuous roller tracks.

Alternatively, the rails 92 and 94 could be designed with extension sections, retractable, in the crosspieces 70 and 72. The extension rails can likewise be mounted on a movable device installed by the side of the device for the direct extraction of the upper tool.

Claims

1. Press apparatus comprising a lower support for a lower tool, an upper support for an upper tool situated above the lower support and means for the vertical displacement of the lower support, whereby said support performs an intermittent movement during the course of which said support may occupy an upper position in which the lower tool can interact with the upper tool in order to grip material between the said tools and a lower position in which the lower tool is moved away from the upper tool in order to enable the material to be released from the space situated between the said tools, the apparatus including means for guiding the vertical movement of the lower support, the means for the vertical displacement of the lower support comprising:

26

2. Apparatus in accordance with Claim 1, wherein the base presents at least two similar cam surfaces arranged in such a way as to form at least one pair of cam surfaces situated opposite each other, the apparatus comprising at least one first pair of operating rods associated with the said first pair of cam surfaces, the end of each rod of the first pair being fitted with a roller capable of interacting with one of the cam surfaces of the first pair of cam surfaces and the first ends of the rods of the first pair being connected by a first horizontal coupling shaft extending between the two cam surfaces, the first end of the control rod being connected to the said first coupling shaft.

3. Apparatus in accordance with Claim 2, wherein at least one supplementary module of rods comprising a connecting rod, a second pair of operating rods similar to the operating rods of the first pair and a second horizontal coupling shaft connecting the first ends of the operating rods of the second pair and also at least one supplementary module of cams comprising a second pair of cam surfaces situated opposite each other, the cam surfaces of the second pair being analogous to those of the first pair and offset in relation to these latter, the connecting rod being connected by a first end to the second coupling shaft and by a second end to the first coupling shaft.

4. Apparatus in accordance with Claim 3, wherein there is provided a second supplementary module of rods including a connecting rod, a third pair of operating rods analogous to the operating rods of the first and 27 second pairs and a third horizontal coupling shaft interconnecting the first ends of the operating rods of the third pair, as well as a second supplementary module of cams including a third pair of cam surfaces situated opposite each other, the cam surfaces of the third pair being analogous to those of the first and second pairs and offset in relation to these latter, the connecting rod of the second supplementary rod module being connected by a first end to the third coupling shaft and by a second end to the second coupling shaft.

5. Apparatus according to any one of Claims 1 to 4, wherein the driving means of the second end of the control rod comprises a motor having an output shaft and a transmission device fast in rotation with the output shaft of the motor and connected to the second end of the control rod by a connecting shaft parallel to the output shaft of the motor and spaced therefrom, this connecting shaft being mounted to rotate freely about the geometric axis thereof in relation to at least one of the two elements consisting of the transmission device and the second end of the control shaft.

6. Apparatus according to any one of Claims 1 to 5, wherein the upper support comprises means forming slides in relation to which the upper tool is capable of sliding in a substantially horizontal plane in order to be placed in position in the press apparatus and extracted from the latter, and that it comprises means for securing the upper tool in relation to the said means forming slides, in order to fix the said tool in the 28 operating position.

7. Apparatus according to Claim 6, wherein the upper support comprises two parallel side rails and a frame to which the upper tool is capable of being affixed, this frame being fitted with projecting side elements capable of interacting with the rails in order to slide therein.

8. Apparatus according to Claim 7, wherein the projecting side elements comprise roller bearings.

9. Apparatus according to either Claim 7 or 8, wherein the means for securing the upper tool in relation to the means forming slides comprise stops or pins capable of interacting with the projecting side elements of the frame.

10. Apparatus according to any one of Claims 7 to 9, wherein extension rails capable of being positioned in the continuation of the open free ends of the side rails of the frame are provided in order to extend these latter rails by a length such that the frame is able to slide in the extension rails at least as far as a position in which the upper tool is completely offset in relation to the lower support.

11.. Press apparatus constructed and arranged to function as herein described and illustrated with reference to the drawings.

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12. Receptacles or containers when produced on an apparatus according to any preceding claim.