Forming tool and method for producing a packaging

Abstract

A pre-punched material sheet for constructing a packaging trough, the material sheet includes a sub-area that has been punched out incompletely so that the sub-area is connected to a residual area of the material sheet through a plurality of retaining lugs. The material sheet is positioned on top of a female die part of a forming tool and the sub-area at least partially covers an opening of a forming cavity of the female die part. The residual area of the material sheet may be clamped in position against the female die part. The sub-area of the material sheet is sucked onto an insert in the forming cavity using a vacuum. The insert is vertically movable in the forming cavity from a first position to a second position to draw the sheet into the forming cavity and thereby form the packaging trough.

Claims

1. A method for producing a packaging, the method comprising the steps of: providing a pre-punched material sheet from which a sub-area has been punched out incompletely such that the sub-area is connected to a residual area of the material sheet through a plurality of retaining lugs; positioning the pre-punched material sheet on top of a female die part of a forming tool such that the sub-area of the material sheet at least partially covers an opening of a forming cavity of the female die part; clamping the residual area of the material sheet in position against a contact surface of the female die part; sucking the sub-area of the material sheet onto an insert within the forming cavity using a vacuum while the insert is at a first position, wherein the insert is vertically movable in the forming cavity of the female die part between the first position and a second position; and moving the insert from the first position in a displacement direction further into the forming cavity toward said second position to draw the sub-area of the material sheet into the forming cavity and form the material sheet into a packaging trough.

2. The method according to claim 1, further comprising the step of tearing the retaining lugs to separate the sub-area from the residual area of the material sheet during the moving the insert from the first position further into the forming cavity toward the second position step.

3. The method according to claim 1, wherein the providing the pre-punched material sheet step comprises the step of pre-punching the material sheet to incompletely punch out the sub-area of the material sheet so that the sub-area remains connected to the residual area of the material sheet through the plurality of retaining lugs.

4. The method according to claim 1, wherein the forming cavity comprises one or more sidewalls that form an incline, wherein the incline widens the forming cavity in a direction from within the forming cavity towards the opening of the forming cavity.

5. The method according to claim 1, wherein the material of the material sheet is essentially not thermoplastically deformable.

6. The method according to claim 1, wherein the material of the material sheet comprises natural fibers, cardboard and/or paper.

7. The method according to claim 1, further comprising the step of positioning a thermoplastic film layer on top of the material sheet that is positioned on top of the female die part.

8. The method according to claim 7, further comprising the step of forming the thermoplastic film layer into the packaging trough by applying compressed air from a side of the thermoplastic film layer opposite the material sheet.

9. The method according to claim 7, further comprising the step of heating the thermoplastic film layer after the positioning the film layer on top of the material sheet step using a heating unit disposed on a side of the film layer opposite the female die part.

10. A forming tool for producing a packaging trough, the forming tool comprising: a female die part comprising a contact surface and a forming cavity having an opening, wherein the forming cavity of the female die part includes an insert, the insert being vertically movable from a first position in a displacement direction further into the forming cavity to a second position; a clamping unit, which is configured for clamping a residual area of a material sheet in position against the contact surface of the female die part when the material sheet has been positioned on top of the female die part such that a sub-area of the material sheet at least partially covers the opening of the forming cavity of the female die part, wherein the sub-area of the material sheet is connected to a residual area of the material sheet through a plurality of retaining lugs; and a vacuum unit in fluid communication with the forming cavity and configured for sucking the sub-area of the material sheet onto the insert disposed at the first position using a vacuum.

11. The forming tool according to claim 10, wherein the forming cavity comprises a forming incline that widens in the direction from within the cavity towards the opening of the forming cavity.

12. The forming tool according to claim 10, further comprising a compressed-air unit disposed to apply compressed air on a thermoplastic film layer in the direction towards the material sheet when the thermoplastic film layer is positioned on top of the material sheet when the material sheet is positioned on top of the female die part, the compressed air being appliable to a side of the thermoplastic film layer opposite the material sheet.

13. The forming tool according to claim 12, further comprising a heating unit for heating the thermoplastic film layer when the thermoplastic film layer has been positioned on top of the material sheet on top of the female die part, the heating unit being disposed on the side of the film layer opposite the female die part.

14. The forming tool according to claim 13, wherein the heating unit is movable towards and away from the female die part in a direction parallel to the displacement direction of the insert.

15. A packaging machine, comprising: the forming tool for producing a packaging from the material sheet according to claim 10; and a punching station upstream of said forming tool, the punching station configured for pre-punching the material sheet by incompletely punching out the sub-area of the material sheet so that the sub-area remains connected to the residual area of the material sheet through the plurality of retaining lugs.

16. The packaging machine according to claim 15, further comprising a conveying unit downstream of the punching station, wherein the conveying unit is operable to position the material sheet that has been pre-punched by the punching station on top of the female die part of the forming tool such that the sub-area of the material sheet at least partially covers the opening of the forming cavity of the female die part.

Description

DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) In the following, an advantageous embodiment of the present invention will be explained in more detail making reference to a drawing, in which the individual figures show:

(2) FIG. 1 is a schematic view of one embodiment of a packaging machine comprising a forming tool and a punching station in accordance with the teachings of the present disclosure;

(3) FIG. 2 is a schematic top view of one embodiment of a pre-punched material sheet in accordance with the teachings of the present disclosure;

(4) FIG. 3 is a perspective schematic view of one embodiment of a packaging trough produced with a method in accordance with the teachings of the present disclosure;

(5) FIG. 4A is a schematic view of one embodiment of a forming tool in accordance with the teachings of the present disclosure showing one sequence of the operating conditions during production of a packaging in accordance the present disclosure;

(6) FIG. 4B is a schematic view of the embodiment of a forming tool of FIG. 4A showing another sequence of the operating conditions during production of a packaging in accordance the present disclosure;

(7) FIG. 4C is a schematic view of the embodiment of a forming tool of FIG. 4A showing another sequence of the operating conditions during production of a packaging in accordance the present disclosure;

(8) FIG. 4D is a schematic view of the embodiment of a forming tool of FIG. 4A showing another sequence of the operating conditions during production of a packaging in accordance the present disclosure; and

(9) FIG. 5 is a schematic top view of one embodiment of material blanks to be formed into packaging troughs in a method in accordance the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

(10) The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures.

(11) The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled.

(12) FIG. 1 shows a packaging machine 1 according to an embodiment. The packaging machine 1 comprises a punching station 3 as well as a forming tool 5, both provided on a machine frame 7. The punching station 3 comprises a punching tool upper part 9 and a punching tool lower part 11. By means of a conveying unit 15, a material web 13 is taken from a supply roll 17, which is attached to the machine frame 7, and fed to the punching station 3. The conveying unit 15 may comprise e.g. clamp chains guided on the machine frame 7 on both sides of the material web 13 and used for clampingly holding the material web 13.

(13) The punching station 3 is configured for pre-punching the material web 13. In particular, a material sheet 19, which constitutes part of the material web 13, is pre-punched. FIG. 2 shows, in a schematic top view, a material sheet 19 that has been pre-punched by the punching station 3. In the embodiment shown, this material sheet 19 was also separated from the rest of the material web 13 during pre-punching. This, however, is not absolutely necessary. In addition, it would also be imaginable that, instead of the material web 13, material sheets 19 which have already been separated are fed to the punching station 3.

(14) In the embodiment shown, the punching station 3 punches, during pre-punching of the material sheet 19, four sub-areas 21 out from the material sheet 19 by incomplete punching-out, so that the sub-areas 21 remain connected to a residual area 25 of the material sheet 19 through a plurality of retaining lugs 23. The sub-areas 21 each correspond to a region that will be formed into a packaging trough 27 with the forming tool 5 later on. In the embodiment shown, packaging troughs 27 having the shape shown in FIG. 3 are to be produced, i.e. packaging troughs 27 with a rectangular base area 29 and outwardly tilted sidewalls 31. Of course, also other configurations would be imaginable for the packaging trough 27, such as a packaging trough 27 having an arbitrary polygon, a circle or an ellipse as a base area 29. The configuration of the sub-areas 21 of the material sheet 19 which are to be punched out incompletely may be adapted to the respective desired shape of the packaging trough 27.

(15) In the embodiment shown, four sub-areas 21 are punched out incompletely from each material sheet 19 by the punching station 3, as mentioned above. It follows that four packaging troughs 27 can be produced simultaneously when the material sheet 19 is further processed by the forming tool 5 as described hereinafter. Of course, it would also be imaginable to punch out any other number of sub-areas 21 incompletely from the material sheet 19. In particular, it would also be imaginable to punch out only one sub-area 21 incompletely from a material sheet 19 and to produce each individual packaging trough 27 separately.

(16) After pre-punching, the material sheet 19 is transferred to the forming tool 5 for further processing. In particular, the pre-punched material sheet 19 is positioned on top of a female die part 33 of the forming tool 5. In the embodiment shown, this is done by advancing the material sheet 19 by means of the conveying unit 15. However, it would e.g. also be imaginable to feed the material sheet 19 manually to the forming tool 5.

(17) The forming tool 5 comprises the female die part 33 as well as a cover part 35. FIG. 4A shows the forming station 5, in part, in an open operating condition. In the open operating condition, the female die part 33 and the cover part 35 are spaced apart such that the material sheet 19 can be positioned between the female die part 33 and the cover part 35. In FIG. 4A, the material sheet 19 has already been positioned, by means of the conveying unit 15, on top of the female die part 33 such that each of the incompletely punched-out sub-areas 21 of the material sheet 19 covers a respective opening 37 of an associated forming cavity 39 of the female die part 33. In addition, a thermoplastic film layer 41 has been positioned on top of the material sheet 19 on the material sheet side facing away from the female die part 33. In the embodiment shown, the thermoplastic film layer 41 is unwound from a suitable supply roll 43 of the forming tool 5 (cf. FIG. 1).

(18) After the pre-punched material sheet 19 and the thermoplastic film layer 41 have been positioned between the female die part 33 and the cover part 35 of the forming tool 5, the forming tool 5 is closed by moving the female die part 33 and the cover part 35 towards each other. The resultant operating situation is shown in FIG. 4B. On its end facing the female die part 33, the cover part 35 comprises a clamping unit 45, which, in the embodiment shown, is configured as a grid corresponding substantially to the shape of the residual area 25 of the material sheet 19. In the closed condition of the forming tool 5, the clamping unit 45 clamps the residual area 25 of the material sheet 19 against a contact surface 47 of the female die part 33. Also the thermoplastic film layer 41 provided on top of the material sheet 19 is clamped against the contact surface 47 of the female die part 33 by means of the clamping unit 45 and is thus immobilized. Preferably, an air-tight sealed inner space is defined, in the closed condition of the forming tool 5, by the female die part 33 and the cover part 35 together with the material sheet 19 clamped in position therebetween and the thermoplastic film layer 41 clamped in position therebetween.

(19) The forming tool 5 comprises vertically movable inserts 49, each forming cavity 39 of the female die part 33 having provided therein a respective one of these inserts 49. Each of the inserts 49 is vertically movable along a displacement direction V inside the respective forming cavities 39. The displacement direction V is parallel to the direction along which the female die part 33 and the cover part 35 of the forming tool 5 are moved relative to each other so as to close or open the forming tool 5. In FIG. 4A and 4B, each of the vertically movable inserts 49 is shown at its respective starting position, which corresponds to a maximum extended position. At the starting position, a holding plate 51 of a vertically movable insert 49 is located substantially on a level on which it is flush with the opening 37 of the respective forming cavity 39 of the female die part 33. The vertically movable inserts 49 each comprise channels 53 terminating in openings, which are formed in the holding plate 51 and which face the material sheet 19. The channels 53 communicate with a vacuum unit 55, which is configured for sucking the sub-areas 21 of the material sheet 19 onto the holding plate 51 of the respective vertically movable insert 49 by means of a vacuum applied through the channels 53. After the forming tool 5 has been closed, each of the sub-areas 21 is, at least sectionwise, sucked by means of the vacuum unit 55 onto the respective vertically movable insert 49 and is held on the latter.

(20) After the incompletely punched-out sub-areas 21 have been sucked onto the respective vertically movable insert 49, the vertically movable inserts 49 are moved along the displacement direction V from the starting position further into the forming cavities 39. In the course of this process, the sub-areas 21 of the material sheet 19 are drawn into the forming cavities 39 and are thus each formed into a packaging trough 27. FIG. 4C shows the situation after the vertically movable inserts 49 have been fully moved in. Due to the fact that the incompletely punched-out sub-areas 21 were sucked onto the inserts 49 during moving-in of the inserts 49, the sub-areas 21 were formed into packaging troughs 27 while they were drawn into the respective forming cavity 39 through engagement with sidewalls of the forming cavity 39, in particular with forming inclines 57 of the forming cavities 39, which widen in the direction of the openings 37 of the forming cavities 39. Since the residual area 25 of the material sheet 19 is clamped against the contact surface 47 of the female die part 33 during moving-in of the vertically movable insert 49, the retaining lugs 23 will tear while the sub-areas 21 are drawn into the forming cavities 39 and the packaging troughs 27 will be separated from the residual area 25 of the material sheet 19.

(21) The cover part 35 of the forming tool 5 has provided therein a heating unit 59, which is movable towards the female die part 33 and away from the female die part 33 parallel to the displacement direction V of the vertically movable inserts 49. In FIG. 4A and 4B, the heating unit 59 is shown at a stow-away position, at which it has been moved inside the cover part 35 away from the female die part 33 to the maximum possible extent. After the forming tool 5 has been closed, the heating unit 59 is moved from the stow-away position towards the female die part 33 to a heating position, which is shown in FIG. 4C and 4D. As can be seen from FIG. 4C, the heating unit 59, when occupying the heating position, is located adjacent the thermoplastic film layer 41 and will thus be able to heat the latter, so as to improve the deformability of the film layer 41.

(22) After the packaging troughs 27 have been formed by drawing the incompletely punched-out sub-areas 21 into the forming cavities 39, the heated thermoplastic film layer 41 is formed-in into the packaging troughs 27 by applying compressed air from the side of the film layer 41 facing away from the female die part 33. For this purpose, the forming tool 5 may comprise a corn-pressed-air unit 61 that is capable of introducing air into the interior of the cover part 35 of the forming tool 5. Due to the pressure rise inside the cover part 35, the thermoplastic film layer 41 will be formed-in into the packaging troughs 27, as shown in FIG. 4D. In this way, the packaging troughs 27 are provided with an interior film layer. The provision of such a film layer is, however, not absolutely necessary and the thermoplastic film layer 41 may also be omitted completely. Alternatively, the thermoplastic film layer 41 may also be connected to the packaging trough 27 in a separate work station downstream of the forming tool 5.

(23) As an alternative, it would also be imaginable to form, instead of the incompletely punched-out sub-areas 21 of the pre-punched material sheet 19, fully punched-out material blanks 71 into packaging troughs 27. FIG. 5 shows exemplarily four such material blanks 71 having a shape of such a nature that packaging troughs 27 of the type shown in FIG. 3 can be formed therefrom.

(24) The material blanks 71 can be positioned on top of the female die part 33 of the forming tool 5 such that each of them covers, at least partially, an opening 37 of a forming cavity 39 of the female die part 33. In order to facilitate the correct positioning of the material blanks 71, the female die part 33 may have provided thereon positioning elements 73, which can be used for orienting the material blanks 71 relative thereto. Such positioning elements 73 are shown in FIG. 4A to 4D by dashed lines as a possible modification. When fully punched-out material blanks 71 are processed, clamping of the material against the contact surface 47 of the female die part 33 can be dispensed with, and the clamping unit 45 of the forming station 5 can therefore be omitted as a modification. As for the rest, a forming station 5 of the above-described kind may be used.

(25) After having been positioned, the respective material blanks 71 are sucked, by means of a vacuum applied by the vacuum unit 55, onto the vertically movable insert 49 provided in the associated forming cavity 39 of the female die part 33. Subsequently, each of the inserts 49 is moved from the starting position along the displacement direction V further into the forming cavity 39. This has the effect that the respective material blank 71 is drawn into the forming cavity 39 and thus formed into a packaging trough 27.

(26) It is also imaginable to position a thermoplastic film layer 41 on top of the material blanks 71 on top of the female die part 33 and, in addition, to optionally form-in the thermoplastic film layer 41 into the packaging troughs 27 through compressed air from the compressed-air unit 61.

(27) From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting.

(28) The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention.

(29) As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms having and including and similar terms as used in the foregoing specification are used in the sense of optional or may include and not as required. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.