EP0573811A1 - Tubular bag machine for continuously making bags with side folds - Google Patents

Abstract

Tubular-bag packaging machine having at least one pair of transverse sealing jaws (25) which are mounted on a holding device (15) movable vertically to and fro by means of a connecting rod (14) and which are movable horizontally via a four-bar mechanism, having a crank disc (9) coupled to the connecting rod (14), and having side-fold piercers (23, 24) which are mounted on a guide element (18) so as to be movable transversely to the direction of movement of a foil tube (41). So that the movement of the side-fold piercing tools (23, 24) can be synchronised in an operationally reliable way for the cycle of movement of the remaining tubular-bag packaging machine, especially of the transverse sealing jaws (25), provision is made, according to the invention, for the guide element (18) to be mounted on the holding device (15), and for the guide element (18) to be coupled to an arm (39) which is mounted pivotably on the holding device (15) and which is connected operatively to a rocker lever (33) mounted pivotably on the connecting rod (14), the lower end region of the rocker lever (33) cooperating, in the region of the crank disc (9), with a cam element (11) assigned to the latter. <IMAGE>

Description

The invention relates to a tubular bag machine for producing gusseted packs, the packs being produced from a web-shaped material which is continuously formed by means of a shaped shoulder into a tube with the subsequent formation of a longitudinal seam, the top and bottom seam being formed by means of at least one A pair of cross-welding / cross-sealing jaws rotating cyclically on approximately circular tracks and guided parallel to one another is formed, with a crank disc coupled to a connecting rod, and with gusset plungers which are movably mounted on a guide element transversely to the direction of movement of a film tube.

The manufacture of tubular bags on form, fill, and seal machines is known, for example, from US Pat. No. 4,391,081. The circumferential friction belts lying against a filling tube pull the film web fed from a roll over a shaping shoulder, the initially flat film being formed into a tube. By sealing or welding the the longitudinal seam is formed overlapping edges. The shape shoulder is connected to a filling tube so that the goods to be packaged can be filled into the tube through the filling tube from above. Below the filling tube, the bottom seam and at the same time the top seam of the previous bag are formed by means of a transverse sealing station, the two bags being separated from one another by means of a separating knife. The movement of the cross sealing jaws, which lie transversely to the direction of movement of the bag material, takes place cyclically in one plane in order to be able to transport the filled bag downwards once the sealing has been completed.

From US Pat. No. 4,815,253, a tubular bag machine working in this way has become known, which shows a device for producing stable bags. The side walls are folded inwards below and above the sealing jaws shortly before the sealing by means of side gusset punches. After the sealing has been carried out, the bag is transported downwards, whereby it is brought into a rectangular shape again in a molding chamber formed from two opposite U-shaped elements before its top seam is formed and the separation from the subsequent bag takes place.

It is also state of the art to support the rectangular shape of the bag to be produced in that the filling tube itself has a rectangular cross section, at least in the lower region. However, it is also known to make the entire tube rectangular, the shape shoulder shaping the flat web into a rectangular tube by suitable shaping.

A disadvantage of these intermittently operating packaging machines is that due to downtimes the machine performance is limited in terms of the cross sealing jaw movement and film removal. Particularly due to the very high film acceleration, the frictional connection between the film and the friction belt is no longer guaranteed, so that the set bag length is no longer achieved due to slippage.

In order to eliminate this disadvantage of the intermittent tubular bag machine, a device with continuous operation is described in EP-PS 226 693. In contrast to the previous devices, the wrapping material is continuously drawn off the roll, formed into a tube and fed to the cross sealing station. The longitudinal sealing is also carried out continuously. In this case, the sealing jaws of the transverse sealing station describe an essentially circular path, with considerably higher machine outputs being possible by eliminating the downtimes of the jaw movement. Due to the linear area of the control curve and the displaceable arrangement of the cross seal jaw carrier, there is a sealing / welding path over which the sealing jaws move in synchronism with the film with a suitable drive control. With this tubular bag machine only the production of so-called flat bags is possible.

DE-OS 40 05 078 forms the closest prior art. This publication shows a block bottom station arranged downstream of the transverse sealing station, which has gusset plunger tools which are horizontally movable. The movement of the tools is controlled via a cam track, which is directly assigned to the tools. In this known device it may prove disadvantageous that the cam track for controlling the horizontal movement of the gusset plunger tools is not sufficiently rotating can be synchronized with the movement of the cross sealing jaws and the film tube. Especially with shorter cycle times and higher production speeds, considerable problems can arise.

The object of the present invention is to provide a gusset device for a continuously operating tubular bag machine which, with a simple construction and reliable operation, produces stable bags or bags with an inserted gusset.

The object is achieved by the features of the main claim, the subclaims show further advantageous refinements of the invention.

The device according to the invention is distinguished by a number of considerable advantages. Since the side folding device is moved in the vertical direction synchronously with the cross sealing jaws, no relative speed occurs between the two during the actual workflow. As a result of the fixed spatial relationship created in this way, the work process, as is known in intermittently working machines, can be transferred to the continuously working one. In this way, a perfect quality of the bags can be achieved.

It is particularly advantageous if the vertical movement of the side folding device and transverse sealing jaws runs synchronously throughout the entire machine cycle, since this considerably simplifies the adjustment and conversion work.

In an advantageous embodiment, the synchronous movement is achieved in that the drive of the side folding device is operationally connected to the transverse sealing station is. In particular, a mechanical coupling ensures that the movements are coordinated in every working phase of the tubular bag machine.

It is particularly advantageous if the vertical movement is generated by a connecting rod, the vertical direction of movement of the side folding device being predetermined by means of a guide. This reduces the number of components to a minimum.

In a particularly favorable further development, the working stroke of the gusset plunger is also generated mechanically perpendicular to the direction of movement of the tube material. This makes it possible to operate the entire device without an active drive device, such as pneumatic cylinders, etc. The setting is much easier and can also be carried out by personnel who have not been specially trained or trained.

Overall, a particular advantage results from the fact that the device does not require any supply lines for air or electricity, so that in the event of a supply failure, no unintentional collision of components is possible, which may could result in destruction of the device.

According to the invention, it is also possible to mount a molding box below the side folding device, which is likewise moved up and down in the vertical direction in synchronism with the latter and with the cross sealing jaws. The bag can then be subsequently brought into a rectangular shape again during the sealing of the head seam.

It is particularly advantageous to support the bag from below with a plate during shaping. Due to the still hot bottom seam, a remaining flip can occur be reached to the ground. The bag thus achieves a special stability. However, it is also possible to effect the folding of the bottom seam with an air jet. At the same time, this would have the advantage of improved bottom seam cooling and thus higher seam strength.

It is of particular advantage that the device can be adjusted to different radii of the sealing jaw movement by also adjusting the connecting rod stroke for the side folding device to the changed conditions. This is particularly necessary if large bag formats are to be produced for large radii or high operating speeds of the tubular bag machine are to be achieved for small radii.

In a particularly advantageous embodiment, it is possible to adapt the horizontal working stroke of the side gusset pliers to the different formats without having to change the folding tools. Only minor changes are necessary for this. The elimination of format parts ensures better handling.

In the tubular bag machine according to the invention, both the movement of the transverse sealing jaws and of the gusset plunger tools are thus brought about by a single drive, namely the rotation of the crank disk. It is thus possible in a particularly simple manner to synchronize the vertical movement of the cross sealing jaws and the horizontal movement of the gusset plunger tools. This synchronization is thus present throughout the entire course of movement, not, as in similar devices known from the prior art, only at the beginning and end of the respective movement of a work cycle. Furthermore, it is possible in a particularly simple manner, both the connecting rod stroke of the holding device, ie the vertical one Adjust the stroke of the cross sealing jaws as well as the horizontal stroke of the gusset plunger tools and adapt them to the respective bag sizes, cycle speeds and the like.

Fig. 1

einen fertigen Beutel mit eingelegter Seitenfalte und Standboden in Vorderansicht, Seitenansicht und Draufsicht,

Fig. 2 und Fig. 3

eine Vorderansicht der erfindungsgemäßen Seitenfaltvorrichtung, und

Fig. 4

eine Seitenansicht der erfindungsgemäßen Vorrichtung.

The invention is described below using an exemplary embodiment in conjunction with the drawing. It shows:

Fig. 1

a finished bag with inserted gusset and stand in front view, side view and top view,

2 and 3

a front view of the side folding device according to the invention, and

Fig. 4

a side view of the device according to the invention.

In Fig. 1, a generic bag 1 is shown as it is produced with the help of a side folding device.

The bag has a substantially rectangular cross section. The top and bottom seams 2, 3 are folded inwards from the side surfaces 4. The head area thus forms a gable 5. The bottom area is folded further inwards than the head area, and after the seam is subsequently folded over there is an almost rectangular base area which enables the bag to have a certain stability. However, it is also possible to design both the head and bottom areas in a gable shape.

2 and 3 show a front view of the side folding device according to the invention. The timing belt 6 coming from the main drive drives by means of the toothed pulley 7 and Shaft 8 on a crank disc 9. The shaft 8 is mounted in a frame 10 which is provided for holding the cross sealing station and the side folding device. Between the frame 10 and the crank disk 9 there is a pot curve 11, which in turn is attached to a holding disk 12. The pot curve 11 can be displaced in the direction of rotation relative to the holding disc 12 and can be fixed in a designated position by means of a clamping screw 13.

A connecting rod 14 is mounted on the crank disc 9 and is connected to a holding device 15. The holding device 15 in turn is guided by means of rollers 16 and a guide element 17 such that only a vertical upward and downward movement according to the predetermined connecting rod stroke P is possible.

A further guide element 18 and two guide rods 19, 20 are located on the holding device 15. At the upper and lower ends of the guide element 18 a holding rod 21, 22 is provided, on which the side gusset punches 23, 24 are arranged.

FIG. 4 shows the vertical position of the side gusset punches 23, 24, one in each case being arranged just above or below the sealing jaw 25.

The transverse sealing jaws are arranged in the transverse sealing station to be considered, each via a carrier 26 on a pair of crank arms 27, which in turn are connected via two connecting links 28 to a second pair of connecting rod arms 29 for parallel guidance of the sealing jaws. The resulting four-bar mechanism results in a parallel guidance of the sealing surfaces to one another.

Since both the transverse sealing jaws 25 and the side folding device are now driven by one and the same drive 31 , the assignment sketched in the drawing is retained in the vertical direction over an entire working cycle, as a result of which it is impossible for the gusset punches 23, 24 to strike the sealing jaws 25 after a one-time adjustment. This ensures the highest level of operational safety.

The stroke H required to produce a side fold is generated by the device according to the invention as follows: The pin 32, which is rotatably and axially displaceably mounted in the crank disk 9, rests on the surface of the cup curve 11 and moves when the crank disk 9 rotates Contour. At the point in time at which the side gusset plungers 23, 24 are to be delivered, the pin 32 passes through an elevation of the curve contour, as a result of which delivery takes place in the axial direction. On the pin 32 outside the crank disc 9 is a rocker arm 33 which is pivotally mounted on the joint 34. At the opposite end a further coupling joint 35 is arranged, to which an arm 36 connects. Between the joints 34, 35, a pin 38 pretensioned by means of a spring 37 presses against the rocker arm 33 and thus generates a sufficiently large restoring force for the rocker arm 33 and the bearing force for the cam pin 32.

When generating the working stroke H, the prestressed spring 37 is compressed further. The arm 39, which is pivotably mounted at the pivot point 40 and is fixedly connected to the arm 36, pivots with its upper part essentially horizontally and in the radial direction to the film tube 41. By guiding the link by means of a cam 42 and an elongated recess 43 in the arm 39 the guide element 18 from the position A shown in dashed lines to the position B pushed. After the stroke has been covered, the sealing jaws 25 close in order to carry out the sealing seams 2, 3 and the separating cut.

Shortly before the separation of the sealing jaws 25, the side gusset punches 23, 24 are moved back into position A. This is done in that the pin 32 has passed the raised point of the pot curve 11 and the arms 33, 36, 39 return to their starting position due to the restoring force generated by the spring 37 and transmitted by the pin 38.

A further holding rod 44 can also be arranged on the holding device, to which a U-shaped plate 45 is fastened. The two opposite sheets 45 result in a rectangular shaft when the side folding device is moved together, which additionally brings the bag 1 into a rectangular shape.

The sheets 45 as well as the gusset pliers 23, 24 are format parts and can be exchanged for other parts if the bag geometry is changed. In particular, it is possible to make the bottom seam of a bag with a folding triangle of a known type as flat as possible, so that a base is created.

If the working stroke H is to be changed during a format change, this is possible by vertically displacing the cam 42 on the guide element, so that the guide element is pushed into the position B '.

The durability of a bag can be increased by folding the bottom seam 3 by means of a device 46. The device 46 is below the bag shaft arranged. A swiveling plate, a blowing device or a combination of both can be used here.

The invention is not limited to the exemplary embodiment shown, but there are various modification and modification possibilities for the person skilled in the art within the scope of the invention.

Claims (11)

Tubular bag machine for producing side-gusseted packs, the packs being produced from a web-shaped material which is continuously formed into a tube by means of a shaping shoulder with subsequent formation of a longitudinal seam, the top and bottom seams being cyclically approximated by means of at least one pair circular paths of rotating and parallel cross-sealing / cross-sealing jaws are formed, with a crank disc (9) coupled to a connecting rod (14), and with gusset pliers (23, 24) which can be moved transversely to the direction of movement of a film tube (41) on a guide element (18), characterized in that the guide element (18) is mounted on the holding device (15), and in that the guide element (18) is coupled to an arm (39) which is pivotably mounted on the holding device (15) and which is coupled to a rocker arm (33) is in operative connection, which is pivotable ar is mounted on the connecting rod (14) and its lower end region in the region of the crank disc (9) interacts with a curve element (11) assigned to it. Machine according to Claim 1, characterized in that a horizontally movable pin (32) is mounted on the crank disk (9) in the bearing of the connecting rod (14), which pin engages through the crank disk (9) and has one end against the cam element (11) and the other end of which bears against the rocker arm (33). Machine according to claim 1 or 2, characterized in that the rocker arm (33) is mounted on the connecting rod (14) at its central region by means of a joint (34). Machine according to one of claims 1 to 3, characterized in that in the region of the connecting rod (14) on the holding device (15) there is arranged a longitudinally movable pin (38) which is spring-biased in the direction of the rocker arm (33) and which is used for The rocker arm (33) is pre-tensioned against it. Machine according to one of claims 1 to 4, characterized in that the cam element (11) is designed in the form of a cup cam mounted on a frame (10) of the packaging machine, which is arranged concentrically with the crank disc (8). Machine according to claim 5, characterized in that the cam element is rotatably mounted on the frame (10) and can be fixed in any rotational position relative to the frame (10) by means of a locking device (13). Machine according to one of claims 1 to 6, characterized in that the arm (39) is coupled to the guide element (18) via an elongated hole guide (43). Machine according to one of claims 1 to 7, characterized in that the arm (39) over a plurality of degrees of freedom having coupling joint (35) is connected to the rocker arm (33). Machine according to one of claims 1 to 8, characterized in that the stroke of the connecting rod (14) is adjustable. Machine according to one of claims 1 to 9, characterized in that means (46) for folding over a bottom seam (3) of a bag (1) are arranged on the holding device (15). Machine according to one of claims 1 to 10, characterized in that means (45) for rectangular forming of a bag (1) are arranged on the holding device (15).

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