Working station with a lifting mechanism for a packaging machine

Abstract

The invention relates to a working station, in particular to a deep-drawing station, to a molding station, to a sealing station, to a cutting station or to a punching station, for a packaging machine, comprising a rack supported on the ground; a work unit comprising an upper part and a lower part; and a lifting mechanism which is carried by the rack and by which the lower part of the work unit can be raised and lowered relative to the rack to perform a lower stroke, wherein the lifting mechanism has a drive that comprises at least one shaft extending in a transverse direction; a drive motor engaging at the shaft for rotating the shaft; and at least one gear which is coupled at an input side to the shaft, at which the lower part is supported at an output side, and which converts a rotation of the shaft into the lower stroke of the lower part.

Claims

1. A working station for a packaging machine, comprising a rack supported on the ground; a work unit comprising an upper part and a lower part; and a lifting mechanism which is carried by the rack and by which the lower part of the work unit can be raised and lowered relative to the rack to perform a lower stroke, wherein the lifting mechanism has a drive that comprises at least one shaft extending in a transverse direction; a drive motor engaging at the shaft for rotating the shaft; and at least one gear which is coupled at an input side to the shaft, at which the lower part is supported at an output side, and which converts a rotation of the shaft into the lower stroke of the lower part; wherein the shaft is carried by the rack at a first axial position of the shaft wherein the shaft carries a base at a second axial position of the shaft, the second axial position being offset from the first axial position along the extension of the shaft in the transverse direction; and wherein the base carries the upper part.

2. A working station in accordance with claim 1, wherein the base comprises a frame.

3. A working station in accordance with claim 1, wherein the gear is configured as a coupling gear.

4. A working station in accordance with claim 3, wherein the coupling gear is configured as a slider crank gear or as a centric slider crank gear.

5. A working station in accordance with claim 1, wherein the gear comprises a toggle lever arrangement.

6. A working station in accordance with claim 5, wherein the toggle lever arrangement is stretched in a position with the lower part raised to the maximum.

7. A working station in accordance with claim 1, wherein the gear comprises at least one pair of congruent and mutually spaced apart connecting rods between which a shaft crank rotationally fixedly connected to the shaft is connected in an articulated manner at the input side and the lower part or a support for the lower part is connected in an articulated manner at the output side.

8. A working station in accordance with claim 1, wherein the shaft is rotatably supported in longitudinal supports of the base that are spaced apart from one another in the transverse direction.

9. A working station in accordance with claim 1, wherein the gear comprises at least two individual gears that are spaced apart along the shaft and that are synchronized by means of the shaft for a joint performance of the lower stroke of the lower part.

10. A working station in accordance with claim 1, wherein the lifting mechanism comprises a plurality of synchronized shafts that are spaced apart along the rack and that each have a gear for the joint performance of the lower stroke of the lower part.

11. A working station in accordance with claim 1, wherein, during the lower stroke of the lower part, the lower part is guided at the base, at the upper part, or at a column supporting the upper part at the base.

12. A working station in accordance with claim 1, wherein the upper part is vertically adjustably supported at the base.

13. A working station in accordance with claim 1, wherein the upper part is supported at the base via a plurality of columns.

14. A working station in accordance with claim 1, wherein the drive motor engages at the shaft via a coupling gear.

15. A working station in accordance with claim 14, wherein, in a position with the lower part lowered to the maximum, the torque applied to a drive shaft of the drive motor via the coupling gear is zero or approximately zero.

16. A working station in accordance with claim 14, wherein the coupling gear is configured as a four-bar linkage that comprises a drive shaft of the drive motor; a motor crank connected to the drive shaft; a drive coupling connected in an articulated manner to the motor crank; and a shaft crank rotationally fixedly connected to the shaft and connected in an articulated manner to the drive coupling.

17. A working station in accordance with claim 16, wherein, in a position with the lower part lowered to the maximum the axis of rotation of the drive shaft of the drive motor, the articulated axis between the motor crank and the drive coupling, and the articulated axis between the drive coupling and the shaft crank lie at least approximately in one plane.

18. A working station in accordance with claim 1, wherein the base can be lowered and raised relative to the rack to perform an upper stroke of the upper part.

19. A working station in accordance with claim 18, wherein the lower stroke of the lower part and the upper stroke of the upper part are positively coupled to one another.

20. A working station in accordance with claim 18, wherein the upper stroke of the upper part and the lower stroke of the lower part extend in opposite senses to one another.

21. A working station in accordance with claim 1, wherein the lifting mechanism is adjustable relative to the rack in a longitudinal direction.

22. A working station in accordance with claim 1, wherein the lifting mechanism is supported via a plurality of support members at the rack and is adjustable relative to the rack in the longitudinal direction by means of the support members.

23. A working station in accordance with claim 1, wherein the rack has at least two support sections which extend spaced apart in parallel in the longitudinal direction, at which the lifting mechanism is supported, and along which the lifting mechanism is adjustable relative to the rack.

24. A working station in accordance with claim 1, wherein a fixing device is provided by means of which the position of the lifting mechanism in the longitudinal direction can be fixed at the rack.

25. A working station in accordance with claim 24, wherein the fixing device comprises a spindle drive for setting the longitudinal position of the lifting mechanism.

26. A working station in accordance with claim 25, wherein the spindle drive comprises a spindle attached to the rack; and a spindle nut, with the spindle nut preventing a movement of the lifting mechanism relative to the rack in the longitudinal direction and allowing said movement in a lift direction.

27. A working station in accordance with claim 1, wherein the working station is one of a deep-drawing station, a molding station, a sealing station, a cutting station or a punching station.

Description

(1) The invention will be described in the following by way of example with reference to the drawing. There are shown:

(2) FIG. 1 a perspective view of a working station comprising a lifting mechanism in accordance with a first embodiment of the invention;

(3) FIGS. 2 and 3 different side views of the lifting mechanism in accordance with the invention of FIG. 1; and

(4) FIGS. 4 to 6 different views of a lifting mechanism in accordance with a second embodiment of the invention.

(5) The working station shown in FIG. 1 is a deep-drawing station of a packaging machine, which comprises a rack 11 standing on the ground and having two upper support sections 51 and two lower support sections 37 that extend in a conveying direction, also designated as a longitudinal direction in the following, in which a film web, not shown, is conveyed in a generally known manner through the packaging machine and thus through the deep-drawing station shown in FIG. 1. Chain guides (not shown) are inwardly attached to the support sections 51 to guide conveyor chains that are likewise not shown and that laterally hold the passing-though film web in a generally known manner.

(6) The film plane 55, which is indicated by dotted lines in FIG. 1 and in which the film conveying device, not shown, and the film web are disposed during operation, represents the reference plane for the tool of the deep-drawing station shown. In practice, this reference plane is typically disposed somewhat below the upper margin of the support sections 51. The tool is a working chamber, also designated as a deep-drawing chamber, that comprises a lower part 15 and an upper part 13. The height of this reference plane above the ground, on which the rack 11 of the deep-drawing station and the packaging machine stand, is predefined by the packaging machine so that the movements of the lower part 15 and of the upper part 13 of the working chamber of the deep-drawing station have to be coordinated with the position of the film plane 55.

(7) The lower part 15 and the upper part 13 are carried by a lifting mechanism, explained in more detail below, that is inserted as an independent functional unit into the working station between the two lower support sections 37 and the two upper support sections 51. The lifting mechanism is supported as a whole by the rack 11 and is for this purpose solely supported by means of support members, in the form of rollers 35, at the support sections 37.

(8) The two upper support sections 51 and the two lower support sections 37, at which the lifting mechanism is supported via the rollers 35, are fastened to the outer sides of two plate-like transverse members 53 that are spaced apart in the longitudinal direction and that are supported on the ground by feet 57. The lifting mechanism is consequently located within a frame formed by the rack 11 as a support structure that comprises the two transverse members 53; the two upper support sections 51; and the two lower support sections 37.

(9) The lifting mechanism explained with respect to its basic design with reference to FIG. 1 in the following is subsequently described in more detail in connection with FIGS. 2 to 6.

(10) The basic design of the lifting mechanism comprises, at the bottom, a box-shaped frame composed of two lateral longitudinal supports 20 that extend in the longitudinal direction and that are connected to one another by two transverse supports 22. This frame forms a stable base of the lifting mechanism.

(11) A plurality of—in the embodiment of FIG. 1, three—shafts 17 are rotatably supported in the region of their ends in the longitudinal supports 20 of the frame. The already mentioned support rollers 35 are connected to the end faces of the shafts 17, that is they are not directly connected to the longitudinal supports 20 of the frame.

(12) The support of the lifting mechanism at the rack 11 is consequently characterized in that the shafts 17 are supported via the rollers 35 at the support sections 37 of the rack 11, on the one hand, and in that the shafts 17 carry the longitudinal supports 20 and thus the rack and consequently the total lifting mechanism, on the other hand.

(13) The frame comprising the longitudinal supports 20 and the transverse supports 22 forms a base of the lifting mechanism at which the upper part 13 of the working chamber is directly supported. For this purpose, columns 27 are provided that are each supported vertically above one of the shafts 17 on the longitudinal supports 20 and that support a respective longitudinal member 59 of the upper part 13.

(14) A manually actuable height adjustment is provided between the lower end of each column 27 and the respective longitudinal support 20 of the frame and enables a setting of the spacing between the upper part 13 and the frame such that the position of the upper part 13 can be exactly set with respect to the position of the lower part 15 in the closed state and the film thickness is in particular taken into account in this respect.

(15) Due to the support of the lifting mechanism at the rack 11 via the rollers 35, the lifting mechanism is a carriage that can be moved relative to the rack 11 in the longitudinal direction on the setting up of the packaging machine. The lifting mechanism is not completely freely movable in this respect, but is rather coupled to the rack 11 via a fixing device in the form of a spindle drive comprising a spindle 39 and a spindle nut 41. The spindle 39 extends in the longitudinal direction and is attached to the rack 11 such that it can be rotated about its longitudinal axis by manual actuation. By rotating the spindle 39, the spindle nut 41 connected to the column 27 is acted on in the longitudinal direction and the lifting mechanism is thereby moved in the longitudinal direction. The longitudinal position of the lifting mechanism in the rack 11 can consequently be changed and adapted to a respective application, with the longitudinal position of the lifting mechanism, however, being fixed by the fixing device formed by the spindle drive 39, 41 during the deep-drawing operation.

(16) To perform an upper stroke, which is explained in more detail in the following, the lifting mechanism can be raised and lowered as a whole. This means that the frame 20, 22 together with the upper part 13 supported via the columns 27 and with the lower part 17 carried by the shafts 17 can be raised and lowered relative to the rack 11. To make this upper stroke possible, the spindle nut 41 is longitudinally displaceably supported at the respective column 27.

(17) The lower part 15 is supported at the shafts 17 via a respective gear described in more detail in the following of which a respective pair of congruent and mutually spaced apart connecting rods 23 is shown in FIG. 1 between which a support 16 of the lower part 15 is connected in an articulated manner.

(18) The shafts 17 are connected to one another by a common synchronization coupling 43, not shown in FIG. 1, and are thereby mechanically synchronized. The actuation of the synchronization coupling 43 for a synchronous rotation of the shafts 17 takes place by a drive motor 19 arranged outside the frame 20, 22 at the level of the shafts 17. The motor 19 is supported at the transverse support 22 of the frame at the rear in FIG. 1 and is installed transversely to the extent that the drive shaft, not shown in FIG. 1, of the motor 19 extends in parallel with the shafts 17.

(19) A respective outwardly projecting lug 61 is fastened to the outer sides of the two supports 16 of the lower part 15 and is guided along one of the columns 27 supporting the upper part 13 at the longitudinal support 20 of the frame. The lower part 15 is hereby guided at the upper part 13 when a lower stroke is performed. In this way, the lower part 15 and the upper part 13 are precisely aligned relative to one another.

(20) FIGS. 2 to 6 show a first embodiment (FIGS. 2 and 3) and a second embodiment (FIGS. 4, 5 and 6) of a lifting mechanism in accordance with the invention. The lifting mechanism in accordance with FIGS. 2 and 3 corresponds to the lifting mechanism of the working station shown in FIG. 1. The lifting mechanism in accordance with FIGS. 4, 5 and 6 is generally designed like the lifting mechanism in accordance with FIGS. 2 and 3, but has a smaller working length provided for smaller tools and is for this purpose provided with only two shafts 17, whereas the lifting mechanism in accordance with FIGS. 2 and 3 has three shafts 17 arranged behind one another in the longitudinal direction.

(21) In some representations, some components are not shown in order to illustrate special features of the design. For example, in FIG. 2a, the roller 35 at the left gear and the connecting rod 23 at the front in this side view are not shown. In FIG. 2b, for example, the rollers 35 and the front connecting rods 23 are not shown for any one of the three gears. The motor shaft 29 can, in contrast, be recognized in FIG. 2b. This applies correspondingly to FIGS. 3a and 3b. In addition, FIGS. 2a and 3a each show a front support section 37, whereas a rear support section 37 of the rack is shown in FIGS. 2b and 3b. In FIGS. 4, 5 and 6, the lifting mechanism is shown without components belonging to the rack in each case.

(22) Due to the generally identical design, the following explanations relating to the embodiment of FIGS. 2 and 3 also apply to the embodiment of FIGS. 4, 5 and 6.

(23) In FIGS. 2a and 2b, the respective lower part 15 of which a longitudinal support 16 is shown is open in the position lowered to the maximum, i.e. the working chamber comprising the lower part 15 and the upper part 13 is open. In contrast, FIGS. 3a and 3b show the state of the working station when the working chamber is closed and in which the lower part 15 is in the position raised to the maximum.

(24) The lifting mechanism is here moreover provided with an upper stroke function for the upper part 13: When the chamber is open in accordance with FIGS. 2a and 2b, the upper part 13 is in the position raised to the maximum, whereas the position of the upper part 13 lowered to the maximum when the working chamber is closed is shown in FIGS. 3a and 3b.

(25) The lower stroke movement of the lower part 15 and the upper stroke movement of the upper part 13 are positively coupled to one another via the shafts 17 and extend in opposite senses to one another, i.e. a raising of the lower part 15 is connected to a lowering of the upper part 13, and vice versa. The shafts 17 are synchronized with one another via a synchronization coupling 43 that engages at the shafts 17 via a respective shaft crank 25 rotationally fixedly connected to the respective shaft 17. The synchronization coupling 43 is in each case pivotally connected in an articulated manner to the shaft cranks 25 about an articulated axis 81.

(26) The rotation of the shafts 17 which are synchronized with one another takes place by means of a single electric motor 19 that engages at the shaft 17 at the left in the Figures, and indeed via a motor crank 31 that is connected to a drive shaft 29 of the motor 19 and that is connected in an articulated manner via a drive coupling 33 to the shaft crank 25 of this shaft 17.

(27) Starting from the open position in accordance with FIGS. 2a and 2b, the motor 19 rotates the motor crank 31 counterclockwise by approximately 150°, whereby all the shaft cranks 25 together with the shafts 17 likewise synchronously rotate counterclockwise, and indeed by an angle of rotation of approximately 100°. A reduction is consequently provided between the motor crank 31 and the shafts 17.

(28) The rotation of the motor cranks 25 is converted into a movement of the two connecting rods 23 in each case, whereby the respective longitudinal support 16 of the lower part 15 is moved upwardly.

(29) As already mentioned elsewhere, the design of the two individual gears at the left end and at the right end of each shaft 17 is identical, i.e. each shaft 17 engages at two points spaced apart in the transverse direction by a respective arrangement of the motor crank and the connecting rods 23 at the respective longitudinal support 16 of the lower part 15. The motor 19 is, in contrast, only connected to the shaft crank 25 at the rear in the side view selected here via the motor crank 31 and the drive coupling 33.

(30) The design of the lifting mechanism selected in the two embodiments described here is advantageous in a plurality of aspects:

(31) When the working chamber is closed in accordance with FIGS. 3a and 3b, the toggle lever arrangements, which are each formed by a shaft crank 25 and the associated connecting rods 23, are each in a vertically stretched position. In this neutral position of the gear, the lower part 15 consequently does not exert any torque on the shafts 17. The total effective weight is transferred directly via the shafts 17 and the support rollers 35 connected to the shafts 17 into the longitudinal supports 37 and thus into the rack of the working station.

(32) In the open position of the working chamber in accordance with FIGS. 2a and 2b, the four-bar linkage formed by the drive shaft 29 of the motor 19, by the motor crank 31, by the drive coupling 33, and by the shaft crank 25 are likewise in a neutral position in the sense of a stretched state in which the relevant axes are disposed in a common plane. The relevant axes are the axis of rotation 65 of the drive shaft 29 of the motor 19, the articulated axis 63 between the motor crank 31 and the drive coupling 33, and the articulated axis 67 between the drive coupling 33 and the shaft crank 25. This stretched state has the result that the shaft crank 25 cannot rotate further clockwise and that the total effective weight of the lower part 15 and of the gear consequently cannot exert any torque on the drive shaft 29 of the motor 19. When the working chamber is open, i.e. when the lower part 15 is lowered to the maximum, the motor 19 is thus free of external forces. The motor 19 consequently does not need to be acted on by a holding current to generate a torque counteracting a weight. In particular when the working chamber is open, the motor 19 that is free of forces in this respect can be replaced without problem or separated from the motor crank 31 for other reasons.

(33) The movable parts and their connections are moreover optimized and arranged relative to one another such that, when taking into account an upper stroke movement of the upper part 13 explained in more detail in the following, an ideal force development or torque development without disadvantageous force or torque peaks results over the total opening or closing movement of the working chamber, that is over the total angle of rotation of the motor crank 31 or of the shafts 17.

(34) With respect to the shafts 17 and thus to a reference system only of the lifting mechanism, the above-described movement routine of the lower stroke of the lower part 15 is independent of the manner of the support of the lifting mechanism at the rack 11 (cf. FIG. 1) or at the support sections 37 of the rack. With regard to the rack 11 supported on the ground and thus to the film plane 55 that adopts a fixed height with respect to the rack 11, the maximum stroke distance of the lower part 15 relative to the shafts 17 (as mentioned in the introductory part, e.g. 105 mm), in contrast, does not correspond to the effective working stroke of the working chamber (e.g. 80 mm). The reason for this is that the rotation of the shafts 17 effected for the performance of the lower stroke of the lower part 15 simultaneously results in a lowering of the shafts 17. The lowering of the shafts 17 results in a downward movement of the total lifting mechanism, including the upper part 13 supported via the columns 27 at the shafts 17 relative to the rack and thus relative to the film plane 55. The upper stroke e.g. amounts to 25 mm so that the mentioned maximum effective working stroke of 105 mm−25 mm=80 mm results that is designed as sufficiently large for applications having a required effective working stroke of the working chamber of approximately 75 mm.

(35) The lowering of the shafts 17 is achieved by an eccentric support of the shafts 17 at the support rollers 35. This concept can be reproduced particularly well by means of FIGS. 2a and 3a in which the support roller 35 is not shown at the left gear in each case. Instead, it can be recognized there that the axes of rotation 18 of the shafts 17 do not coincide with the axes of rotation of the support rollers 35 that are also designated as eccentric axes 36 in the following. The eccentricity, i.e. the radial spacing between the axis of rotation 18 of the shaft 17 and the eccentric axis 36 determines—at a given maximum angle of rotation of the shaft 17—the maximum stroke distance of the upper stroke.

(36) When the working chamber is closed in accordance with FIG. 3a, that is in the respective stretched state of the toggle lever arrangement comprising the shaft crank 25 and the connecting rods 23, the eccentric axes 36 are each also disposed in the common vertical plane of the articulated axis 71, the articulated axis 73 and the shaft rotational axis 18. The eccentric axes 36 are in this respect each disposed vertically above the axis of rotation 18 of the respective shaft 17, i.e. the shafts 17 and thus the total lifting mechanism, in particular including the upper part 13, are lowered to the maximum with respect to the rack.

(37) When the chamber is, in contrast, open in accordance with FIG. 2a, the shafts 17 and thus the upper part 13 are raised to the maximum with respect to the rack, wherein, starting from an angle of 0° when the chamber is closed in accordance with FIG. 3a, a common plane of the shaft axis of rotation 18 and the eccentric axis 36 includes the angle of approximately 100° to the vertical already mentioned above. This angle is the maximum angle of rotation of the shafts 17.

(38) Since the total lifting mechanism is fixedly connected to the spindle 39 and thus to the rack in the longitudinal direction via the spindle nut 41 cooperating with the right column 27, the evasion movement in the longitudinal direction required due to the eccentric movements of the shafts 17 around the support rollers 35 is not performed by the lifting mechanism, but by the support rollers 35 that roll off the support sections 37 of the rack for this purpose. This can, for example, be understood particularly well in FIGS. 2a and 3a with reference to the positions of the rollers 35 in the longitudinal direction relative to the columns 27 that are in a fixed position in the longitudinal direction.

(39) At the same time, the support rollers 35 enable a positioning of the lifting mechanism in the longitudinal direction by a manual rotation of the spindle 28, as had already been described above in the present case.

(40) In this respect, the lifting mechanism is a carriage that is movable in the longitudinal direction on the support sections 37 of the rack, that has wheels, formed by the support rollers 35 arranged eccentrically with respect to the axes of rotation 18 of the shafts 17, and that has a stable base formed by the frame comprising the longitudinal supports 20 and the transverse supports 22. In this base, the shafts 17 are rotatably supported that thus support the upper part 13 via the columns 27 and the longitudinal supports 20 and the lower part 15 via the gears that are formed by the shaft crank 25 and the connecting rods 23 respectively.

(41) The above explanations generally also apply to the embodiment of FIGS. 4, 5 and 6 that show a lifting mechanism in accordance with the invention comprising only two shafts 17. The concept of the lifting mechanism in accordance with the invention and its arrangement and support in a rack of a respective working station, as described here, can generally be applied to any desired number of shafts 17 arranged behind one another in the longitudinal direction.

(42) While the open state with the lower part 15 lowered to the maximum and the upper part 13 raised to the maximum is shown in FIGS. 4a, 5a and 6a respectively, FIGS. 4b, 5b and 6b respectively show the state of the lifting mechanism when the chamber is closed.

(43) Furthermore, FIGS. 4 and 6 each show a plate-shaped transverse strut 45 for the lower part 15 connecting the two supports 16 of the lower part 15.

(44) The supports 16 and the transverse strut 45 of the lower part 15 and the longitudinal members 59 of the upper part 13 represent functional blocks for the lower chamber and the upper chamber (not shown) and are provided with the electrical and pneumatic connectors and connections required for the operation of the working chamber.

(45) Furthermore, the symmetrical design of the individual gears can in particular be seen from the representations in FIG. 6a and FIG. 6b in which the support 16 of the lower part 15 and the shaft crank 25 are arranged between the pair of connecting rods 23 in each case. This simplifies the design of the rotary supports between the connecting rods 23 and the support 16, on the one hand, and the connecting rods 23 and the shaft crank 25, on the other hand, since tilt torques and transverse forces resulting therefrom are avoided or at least minimized. The guide lugs 61 for the vertical guidance of the lower part 15 at the columns 27 can consequently be designed comparatively simply. This also underlines the extremely robust and low-maintenance total design of the lifting mechanism.

(46) Furthermore, it can in particular be seen from the representations in FIGS. 4 and 6 that the movable parts for raising and lowering the lower part 15 as well as the rollers 35, eccentrically supported at the shafts 17, for supporting the total lifting mechanism at the rack and for performing the upper stroke are laterally arranged relatively far to the outside and are consequently easily accessible. In addition, the inner space of the lifting mechanism is hereby available for other purposes, in particular for tool-specific components and connection lines.

(47) A further advantage of the lifting mechanism in accordance with the invention is that the integration of the upper stroke movement does not mean any significant additional effort, but only requires the explained eccentric connection between the shafts 17 and the support rollers 35 instead of a generally likewise possible central connection.

REFERENCE NUMERAL LIST

(48) 11 rack 13 upper part 15 lower part 16 support of the lower part 17 shaft 18 axis of rotation of the shaft 19 drive motor 20 longitudinal support 21 base, frame 22 transverse support 23 connecting rod 25 shaft crank 27 column 29 drive shaft 31 motor crank 33 drive coupling 35 support member, roller 36 eccentric axis 37 support section 39 spindle 41 spindle nut 43 synchronization coupling 45 transverse strut 51 support section 53 transverse member 55 film plane 57 foot 59 longitudinal member 61 lug 63 articulated axis 65 axis of rotation 67 articulated axis 71 articulated axis 73 articulated axis 81 articulated axis