GB2247952A

GB2247952A - Apparatus for conveying a flat article

Info

Publication number: GB2247952A
Application number: GB9016819A
Authority: GB
Inventors: Walter Koeppe
Original assignee: Koerber AG
Current assignee: Koerber AG
Priority date: 1989-02-09
Filing date: 1990-07-31
Publication date: 1992-03-18
Anticipated expiration: 2010-07-31
Also published as: GB9016819D0; DE3903783A1; GB2247952B

Abstract

Apparatus for conveying a flat article, in particular an endless material web, with conveying means for moving the article in a predetermined direction and means for monitoring the transverse position of the moved article, characterised in that the monitoring means has a nozzle for directing a stream of a gaseous medium onto an edge region of the article, that on the side of the article opposite the nozzle are provided pressure measuring means for producing a measuring signal for the portion of the gas stream flowing past the edge, and that the pressure sensing means are connected to an evaluating and control arrangement for converting the measurement signal into position signals representing the position of the edge of the article. The signal is used to control the position of a pivotally mounted roller (16b, Fig. 3 not shown) by means of a motor (M). As described the nozzle 43 directs gas onto the edge of web 13 (which may be displaced transversely as indicated by arrow 13a), the gas stream producing a negative pressure in a sensor tube 51. <IMAGE>

Description

1 APPARATUS FOR CONVEYING A FLAT ARTICLE The invention relates to an

apparatus for transporting a flat article, in particular an endless material web, with conveying means for moving the article in a predetermined direction and monitoring means for monitoring the position of the moved article.

In order to ensure accurate processing it is often necessary to convey material webs, in particular paper webs or other flat articles, accurately along a predetermined conveying path and prevent lateral deviations in position. As a rule this is achieved by a continuous monitoring of the position of one edge of the material web or the flat article, deviations from a predetermined position of the edge enabling corrective measures to be taken.

For monitoring the edge of the web optical light sensors are normally used with which a very accurate measurement of position is possible. However, a substantial disadvantage of the optical web edge monitoring is that the optical sensors can easily become soiled in use so that reliable measurements cannot be expected in the long term. The action of cleaning means has usually proved unsatisfactory.

An object of the invention is the further improvement of apparatus of the above described kind, in particular with reference to the maintenance of the lateral position of the transported article transverse the direction of conveyance. Errors in the positional control as a result of soiling of the sensors is to be substantially excluded.

This object is achieved in an apparatus of the above described kind in that the monitoring means has a nozzle directing a stream of gaseous medium on the edge region of the upper surface of the product, that on the side of the article opposite the nozzle are arranged pressure sensing means for producing a measurement signal corresponding to the portion of the gas stream passing by the edge and that the pressure measuring means are connected to an evaluating and control arrangement for processing the measurement signal into positional signals representing the position of the edge of the article. Such a "pneumatic sensor" permits even small deviations of the edge of the transported article from its reference position to be accurately determined so that the article can be returned into its reference position.

According to an advantageous development of the invention there 2 is provided a carrier of generally U-shaped cross-section embracing the edge of the article, in one limb whereof is arranged the nozzle and in the other limb whereof, opposite the nozzle, is arranged the pressure sensing means. This integral construction of the pneumatic sensors is structurally very simple and does not require any separate adjustment of the nozzle with reference to the pressure sensing means during assembly and maintenance.

According to a preferred embodiment of the invention the pressure sensing means has a flow channel opposite the nozzle for receiving the part of the gas stream flowing past the edge and a measuring tube leading into the flow channel and connected to a pressure transducer. The pressure transducer is adapted to produce a measuring signal dependent upon the gas stream in the flow channel and is connected with the evaluating and control arrangement which processes the measurement signal into a positional signal representing the position of the edge of the article. According to a further development of the invention the flow channel has an inlet and an outlet opening for the gas stream and the measuring tube is inclined in the flow direction of the gas stream in the flow channel so that by virtue of the ejector or Venturi principle a negative pressure dependent upon the gas flow in the flow channel is produced which is detected by the pressure transducer and converted to a measurement signal representing a measure for the position of the edge. The provision of the measuring device with such a flow channel as proposed in accordance with the invention reliably ensures that the operation of the measuring device is not affected by soiling. Impurities such as dust particles and the like entrained in the gas stream are removed by the flow channel and cannot be deposited at the points of the measuring device that are critical for the reliability of the measurement.

In a further development of the invention it is provided that the conveying means have at least one guide means for influencing the position of the edge of the article and that the guide means are connected to the evaluating and control arrangement and controlled thereby to guide the edge in dependence upon the positional signals in the sense of maintaining a predetermined position of the edge. This enables an automatic correction of the position of the moved article transverse to its conveying direction.

3 The apparatus of the invention is particularly useful for conveying an endless web of material of paper or the like. In this case the conveying means are constructed and arranged for conveying an endless material web in the longitudinal direction and they have at least one guide means for influencing the position of the material web transverse to its conveying direction. In this case the guide means may be web guide means arranged to be movable transverse to the conveying direction of the material web. In order to make possible an automatic correction of the position of the transported web there is connected to the control arrangement a drive means for displacing the guide means in dependence upon the positional signals in the sense of a maintenance of a predetermined position of the edge.

According to a particular embodiment of the invention, the conveying means is constructed and arranged to convey an endless tipping paper strip from a supply reel via a gumming device to a cutting apparatus o a filter attachment machine of the tobacco processing industry. In this case the guide means is preferably arranged upstream of the gumming device so that the positional control of the material web in accordance with the invention ensures that the subsequent gumming takes place precisely on the locations of the material web intended therefor.

The invention has the advantage that it enables a reliable and exact guidance of the transported articles, in particular a material web, in its predetermined conveying path. The proposed pneumatic sensor ensures accurate sensing of the edge of the articles and reliable avoidance of deviations of the edge position from its reference position. There is no risk of the measurement results and hence the control accuracy being spoiled by soiling of the measuring device. The measuring device thus retains its high measuring accuracy for a long time.

The invention will now be further described by way of example only, with reference to the accompanying drawings in which:- Fig. 1 is a diagrammatic elevation of a filter attachment machine using one embodiment of apparatus according to the invention, Fig. 2 is an enlarged side view of the apparatus of Fig. 1, Fig. 3 is a plan view in the direction of arrow III in Fig. 2, and Fig. 4 is an enlarged sectional view of the apparatus.

4 Fig. 1 shows a filter attachment machine of the tobacco processing industry, by way of example a machine with the trade name MAX made by the applicants, in diagrammatic front elevation.

An entry drum 1 transfers cigarettes produced on a cigarette making machine (not shown) to two staggering drums 2, which align the staggered cigarettes and deliver them in rows of two each with a space between the cigarettes to an assembly drum 3. The filter rods are delivered from a magazine 4 to a cutter drum 6, are cut by two circula17 cutters 7 into double length filter plugs, are staggered on a staggering drum 8, arranged on a displacing drum 9 into a row of plugs arranged one behind the other and deposited by an accelerator drum 11 into the gaps in the cigarette rows on the assembly drum 3.

The cigarette-filter-cigarette groups formed in this way are pushed together so that they lie axially closely adjacent. They are then received by a transfer drum 12.

A tipping papers strip 13 is withdrawn from a reel 14 by means of a takeoff roller 16. The strip 13 is guided around a pre-treater 17 having a sharp edge, gummed by a gumming device 18 and cut on a covered roller 19 by a cutter drum 21. The cut tipping strips are applied to the cigarettefilter groups on the transfer drum 12 and rolled around the cigarettefilter groups on a roller drum 22 by means of a rolling device 23. The finished double filter cigarettes are supplied to a cutter drum 26 via a drying drum 24 and converted to individual filter cigarettes by cutting centrally through the filter plugs, faulty filter cigarettes being rejected at the same time. A turning device 29 cooperating with a transfer drum 27 and a collector drum 28 turns one row of filter cigarettes and simultaneously transfers it into the unturned row of filter cigarettes conveyed by the transfer drum 27 and the collector drum 28. By way of a testing drum 31 the filter cigarettes reach an ejector drum 32 on which head sensing of the filter cigarettes takes place prior to the ejection procedure. A depositing drum 34 cooperating with a braking drum 33 deposits the filter cigarettes on a receiving belt 36.

This filter attachment machine is provided with a conveying device 39 in accordance with the invention for the tipping paper strip 13, comprising a monitoring device 37 for the edge of the web and a guide means 38 for lateral orientation of the tipping paper strip, the device 39 being disposed upstream of the gumming device 18.

Details of the conveying device 39 are shown in Figs. 2 to 4.

The monitoring device 37 comprises a carrier 41 which is generally Ushaped in cross section and has limbs 41a and 42b at least partially embracing the material web 13. As shown in Fig. 4 a nozzle 43 is arranged in the limb 42a and is connected via a pressure regulator 44 (Fig. 2) to a pressure source 46. The pressure regulator 44 produces a constant gas flow which is delivered by the nozzle 43 as a gas stream onto the edge region of the material web 13. In the other limb 42 of the carrier 41, opposite the nozzle, is a flow channel 48 with an inlet and an outlet opening 48a, 48b for the gas stream. A measuring tube 51 inclined with respect to the flow direction 49 of the gas stream extends into the flow channel 48 and is connected with a pressure measuring means in the form of a pressure-voltage transducer 52.

As a result of the injector principle the gas stream in the flow channel 48 produces in the measuring tube 51 a negative pressure which is sensed by the transducer 52. This negative pressure is a measure for the portion of the gas stream 47 delivered by the nozzle 43 and flowing past the edge of the material web 13 and hence also a measure for the position of the edge of the material web transversely of its direction of conveyance. The double arrow 13a shows the deflection possibilities of the material web 13 transversely of its direction of conveyance. In order to detect deviations of the material web 13 from its reference position the material web is so guided between the limbs 42a and 42b of the carrier 41 that one of its longitudinal edges cuts the gas stream 47 and depending upon its lateral deflection in the direction of the arrow 13a breaks or deflects the gas stream to a greater or lesser extent.

In Figs. 2 and 3 the means for conveying the material web 13 are rollers 16, 16a, 16b and 16c of which at least one, e.g. the withdrawal roller 16, can be driven.

The roller l6b is mounted on guide means for the material web 13 in the form of a pivotal frame 53 which is driven by a motor 54 for pivotal movement transversely of the direction of conveyance of the material web in the direction of a double arrow 55 about a pivot axis 56. The pivot axis 56 is fixed relative to the machine frame.

The output of the pressure-voltage transducer 52 is connected to an evaluating and control arrangement 57 which processes the 6 measurement signals generated by the pressure-voltage transducer into position signals representing the position of the edge of the material web. Connected to the output of the evaluating and control arrangement 57 is the drive 54 which in dependence upon the position signals pivots the pivotal frame 53 and therewith the roller l6b in the direction of the double arrow 55 so that on occurrence of deviations in the position of the material web 13 a return movement into its reference position results. Also connected to the evaluating and control arrangement 57 is a display device 58 indicating possible positional deviations so that the operator may if necessary intervene.

On stoppage of the machine the pivotal frame 53 should return into its middle position or into another starting position which can be set by a reference value transmitter 59. For this purpose there is provided a measuring means 61, for example a proximity initiator, which is connected to the evaluating and control arrangement 57 and which detects the momentary position of the pivotal frame 53. By comparing this actual value of the position with the position reference value that can be set in the reference value transmitter 59 a control signal is transmitted to the evaluating and control arrangement 57 and returns the pivotal frame 53 into its desired starting position.

The described apparatus ensures a reliable and durable troublefree control of the position of the material web 13 during its longitudinal conveyance. An important part is played by the pneumatic measuring sensor 41 whereof the construction excludes errors caused by soiling of the measuring devices. This long term reliability of the measurement of the position of the web edge in the pneumatic measuring chamber 41 permits the automatic compensation of the position of the material web when changes in position occur, by way of the evaluating the control arrangement 57 and the drive 54 of the pivotal frame 53.

7

Claims

Patent Claims

1. Apparatus for conveying a flat article, in particular an endless material web, with conveying means for moving the article in a predetermined direction and monitoring means for monitoring the position of the moved article, characterised in that the monitoring means has a nozzle for directing a stream of a gaseous medium onto an edge region of the article, that on the side of the article opposite the nozzle are provided pressure measuring means for producing a measuring signal for the portion of the gas stream flowing past the edge, and that the pressure sensing means are connected to an evaluating and control arrangement for converting the measurement signal into position signals representing the position of the edge of the article.

2. Apparatus according to claim 1, characterised in that a carrier of generally U-shape in cross-section and embracing the edge of the article is provided and that in one limb of the carrier is arranged the nozzle and opposite the nozzle in the other limb is arranged the pressure measuring means.

3. Apparatus according to claim 1 or 2, characterised in that the pressure measuring means has a flow channel opposite the nozzle for receiving the portion of the gas stream flowing past the edge and a measuring tube opening into the flow channel and connected to a pressure transducer, that the pressure transducer is adapted to produce a measurement signal dependent upon the gas stream in the flow channel and that the pressure transducer is connected to the evaluating and control arrangement which processes the measurement signal to a position signal corresponding to the position of the edge of the article.

4. Apparatus according to claim 3, characterised in that the flow channel has an entry and an exit opening for the gas stream and that the measuring tube is inclined in the flow channel with respect to the flow direction of the gas stream so that by a Venturi effect there is produced in dependence upon the gas flow in the flow channel a negative pressure which is detected by the pressure transducer and processed into a measurement signal representing a measure for the position of the edge.

5. Apparatus according to one of claims 1 to 4, characterised in 1 8 that the conveying means have at least one guide means for influencing the position of the edge of the article and that the guide means is connected to the evaluating and control arrangement and is controllable thereby for guiding the edge in dependence upon the position signals in the sense of maintaining a predetermined position of the edge.

6. Apparatus according to one of claims 1 to 5, characterised in that the conveying means are constructed and arranged to guide an endless material web in the longitudinal direction and that they have at least one guide means for influencing the position of the material web transversely of its direction of conveyance.

7. Apparatus according to claim 6, characterised in that the guide means is a web guide means for guiding the material web and arranged to be movable transversely to the direction of conveyance of the material web.

8. Apparatus according to one of claims 5 to 7, characterised in that a drive means is connected to the evaluating and control arrangement for displacing the guide means in dependence upon the position signals in the sense of maintaining a predetermined position of the edge.

9. Apparatus according to one of claims 1 to 8, characterised in that the conveying means are constructed and arranged to convey an endless tipping papers strip from a supply roll via a gumming device to a cutting apparatus of a filter attachment machine of the tobacco processing industry.

10. Apparatus according to claim 9, characterised in that the guide means is arranged upstream of the gumming device.

11. Conveying apparatus as claimed in claim 1, substantially as herein described with reference to the accompanying drawings.

Published 1992 at The Patent Office. Concept House. Cardiff Road. Newport, Gwent NP9 1RH. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Point, Cwmifelinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cra.y. Kent.