Patent Application
20190135460
The invention relates to a dispensing device for being disposed in the forming tube of a tubular bag machine for the portioned dispensation of a flowable, in particular powdery, product according to the preamble of claim 1. Generic dispensation devices are used for filling tubular bags in tubular bag machines. The product can be filled from a storage container into the tubular bag, which is produced in the tubular bag machine, by means of a screw conveyor stored in a rotationally drivable manner in a screw tube. The number of rotations of the screw conveyor—tubular bag in this instance—corresponds to the amount of product which has to be filled into the tubular bag in a defined manner.
From DE 196 28 098 A1, a vertical tubular bag machine is known having a generic dispensation device. At the lower end of the screw tube, a so-called seal is fastened which can be opened and closed in sync with the conveying movement of the screw conveyor. The seal is closed when the screw conveyor is stopped. As soon as the screw conveyor is driven, the seal opens in order to enable filling the tubular bag with the product. The point of closing the seal when the screw conveyor is stopped is to prevent the product from trickling down when the screw conveyor is stopped. In particular powdery products, such as milk powder, can trickle down in small amounts from the end of the screw conveyor even when the screw conveyor is stopped. This uncontrolled and undefined dispensation of the product is unintended and can lead to disruptions in the production of tubular bags, in particular when the trickling product gets into the gap of the tubular bag material to be heat-sealed. As described in DE 196 28 098 A1, the seal consequently serves as a flow barrier by means of which a trickling down of the product when the screw conveyor is stopped is reduced or precluded.
Besides such flow barriers realized as seals, other types of flow barriers for being used at the screw tubes of tubular bag machines are also known. Thus, the flow barrier can also be realized as a sieve, a flap, a cone or a vacuum seal. All functioning elements, which are fastened to the end of the screw conveyor and reduce the amount of product trickling down when the screw conveyor is stopped, are to be understood as being flow barriers in the scope of this invention.
From the state of the art, different fastening options for fastening the flow barriers at the lower end of the screw tube are known. The most commonly used fastening options are those, in which a screw connection is intended between the flow barrier and the screw tube. A disadvantage of such screw connections is that the fastening screws repeatedly become loose unintentionally. Should the fastening screw become loose, however, it falls into the tubular bag below together with the product and can be a cause of risk for consumers of this product. Should the user of a tubular bag machine notice a fastening screw to be missing, large numbers of the tubular bags filled with the product have to be recalled, thus posing a large damage risk.
Alternatively thereto, to fasten the flow barrier at the lower end of the screw conveyor it is also known to fasten the flow barrier at the screw conveyor by means of a weld connection. The disadvantage of this kind of fastening, however, is that the flow barrier cannot be exchanged.
Starting from the state of the art, it is the objective of the present invention to propose a new dispensation device for being disposed in the forming tube of a tubular bag machine, the flow barrier being able to be fastened in an exchangeable manner in said dispensation device and an unintended loosening and falling off of the fastening means being essentially precluded at the same time.
This object is attained by a dispensation device according to the teachings of claim 1.
Advantageous embodiments of the invention are the subject matter of the dependent claims.
The fundamental idea of the dispensing device according to the invention is to use a locking bolt for fastening the flow barrier to the screw conveyor, said locking bolt being inserted into or pushed through a receiving contour at the locking bolt and a second receiving contour at the screw conveyor. When the locking bolt is pushed through, a form fit is formed between the locking bolt and the two receiving contours and thus a falling off of the flow barrier is precluded. Moreover, an unintended loosening of the locking bolt during operation of the dispensing device is generally precluded through the size of the locking bolt and the form fit so that production disruptions are precluded via a falling fastening means as can occur in the known state of the art from falling fastening screws.
In which manner the locking bolt and the two receiving contours for the form-fit connection of the screw conveyor to the flow barrier are realized is generally arbitrary. According to a first alternative, the end cross section of the flow barrier facing towards the screw tube is inserted onto the end of the screw tube. The first receiving contour is realized at the flow barrier like a perforation which entirely engages through the wall of the flow barrier. The wall of the screw tube disposed on the inner side of the wall of the flow barrier has a groove which serves as a second receiving contour. For the form-fit connection between the flow barrier and the screw tube, the locking bolt is inserted such that it engages through the perforation in the wall of the flow barrier and simultaneously engages in the groove at the end of the screw tube therebehind.
According to a second embodiment, the end cross section of the flow barrier facing the screw tube can be inserted into the end of the screw tube. In this instance, the first receiving contour is formed in the flow barrier like a groove, whereas the end of the screw tube comprises at least one perforation as a second receiving contour. For the form-fit connection of the flow barrier and the screw tube, the locking bolt in turn is inserted such that it engages through the perforation in the wall of the screw tube and simultaneously engages into the groove of the flow barrier therebehind in a fixating manner.
How large the groove is at the circumference of the screw tube or at the circumference of the flow barrier is generally arbitrary, as long as a sufficiently form-fit connection is ensured when inserting or pushing through the locking bolt. It is particularly advantageous if the groove annularly surrounds the circumference of the screw tube or the circumference of the flow barrier. Via the annular groove, angle tolerances between the flow barrier and the screw tube can be compensated without problems when fastening the flow barrier to the screw tube since a groove section, in which the flow barrier engages in a fixating manner, is always available regardless of the relative angle between the flow barrier and the screw tube.
The constructional embodiment of the locking bolt is also generally arbitrary. It is particularly advantageous if the locking bolt is realized like a push clamp having two arms which each serve for a form-fit connection between the locking bolt and screw tube. The wall of the locking bolt or the wall of the screw tube has two perforations in each instance when using such a push clamp having two arms so that the two arms can engage through the perforations and then each engage in the groove therebehind in a fixating manner. The two arms of the push clamp are connected to each other via a connecting web. The connecting web also serves for manipulating the push clamp when inserting or extracting the push clamp.
A fixation, which is in particular free of play, when using the push clamp is yielded if the groove and/or the two arms of the push clamp each have a rectangular cross section.
The shape of the perforations in the wall in the flow barrier or in the wall of the screw conveyor is generally arbitrary. It is particularly advantageous if the perforations are realized like slits which tangentially perforate the circumference of the flow barrier or the circumference of the screw tube.
The arms of the installed push clamp should preferably be disposed in a push plane extending orthogonal to the longitudinal axis of the screw tube.
In order to reliably preclude the loosening of the push clamp from the fastening position, the two arms of the push clamp should be at least slightly widened elastically when being pushed through the two perforations in the wall of the flow barrier or the screw tube. Via the subsequent resilience of the two arms of the push clamp when in their fastening position, it is ensured that the push clamp can be extracted only when exerting a sufficiently large removal force, for example by the user. Vibrations alone can no longer budge the push clamp from its fastening position owing to the resilience of the arms of the push clamp.
The push clamp can be secured against an unintended loosening from its fastening position by the connecting web of the installed push clamp being disposed in the gap between the screw tube and the forming tube. In order to prevent an unintended extraction of the push clamp, the distance between the screw tube and the forming tube has to be smaller than the extraction path required for extracting the push clamp. In such a configuration, it is therefore necessary in each instance to pull back the screw tube from the forming tube for mounting or extracting the push clamp since otherwise the push clamp could not be extracted from its fastening position.
In order to ensure a precise relative angle between the flow barrier and the screw tube, for example in motor-driven flow barriers having half-shell-shaped sealing shells in this instance, it is particularly advantageous if at least one anti-rotation element is provided at the flow barrier and engages in the wall of the screw tube in a form-fit manner when disposing the flow barrier at the lower end of the screw tube. Owing to the form fit of the anti-rotation element, a precise mounting angle is ensured between the flow barrier and the screw tube, which facilitates in particular mounting drive elements to the flow barrier.
Constructively, the anti-rotation element can be realized like a protrusion which engages in a cutout at the end cross section of the screw tube in a form-fit manner when disposing the flow barrier at the lower end of the screw tube.
An embodiment of the invention is schematically illustrated in the drawings and is described in an exemplary manner in the following.
In the following,
A dispensing device 40 having a product container 13 is disposed above the forming shoulder 05. The product container 13 is supplied with product via a filling nozzle 14. The product in the product container 13 is, for example, a powder and is stirred by means of a stirrer 16 driven by a motor 15. A screw tube 41 connects in the dispensing device 14 below the product container 13. The screw tube 41 is disposed coaxially to the forming tube 42 on which the film tube 06 is guided. In the screw tube 41, a screw conveyor 43 is rotationally mounted which can be driven by means of a motor 44.
At the lower end of the screw tube 41 is a flow barrier 45 which is made of two half shells driven by a drive device. By driving the half shells (not illustrated in the drawing), the flow barrier 45 can be opened when the screw conveyor 43 is rotating and can be closed when the screw conveyor 43 is stopped. By closing the flow barrier 45 when the screw conveyor 43 is stopped, it is prevented that in particular powdery product 46 trickles down from the lower opening of the screw tub 41 when the screw conveyor is shut off and thus disrupts the transverse sealing process.
At the lower end of the screw tube 41, a receiving contour 48 is provided which is realized like an annular groove. The groove comprises a rectangular cross section. At the flow barrier 45, two slit-shaped perforations 49 are provided in the wall as receiving contours. When mounting the flow barrier 45 to the screw tube 41, the flow barrier 45 is inserted onto the lower end of the screw tube 41 from the bottom, the angle position between the flow barrier 45 and the screw tube 41 being defined by an anti-rotation element 50. The anti-rotation element 50 is realized like a protrusion on the inner side of the wall of the flow barrier 45 and engages in a cutout 51 at the end cross section of the screw tube 41 in a form-fit manner. As soon as the flow barrier 45 is fit onto the end of the screw tube 41 without play, the push clamp 47, which serves as a locking bolt in the scope of the invention, is pushed into the perforations 49 from the side, which extend tangentially along the flow barrier 45, until the push clamp 47 surrounds the circumference of the screw tube 41 with both its arms 52.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2016 205 859.2 | Apr 2016 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/055233 | 3/7/2017 | WO | 00 |
