GB2069930A

GB2069930A - Depositing bronze powder on cigarette paper

Info

Publication number: GB2069930A
Application number: GB8038045A
Authority: GB
Original assignee: Hauni Werke Koerber and Co KG
Current assignee: Koerber AG
Priority date: 1979-11-29
Filing date: 1980-11-27
Publication date: 1981-09-03
Also published as: IT1134227B; DE2948108A1; GB2069930B; IT8025915A0; DE2948108C2

Abstract

Bronze powder is applied to gummed areas of a travelling strip of cigarette paper using a depositing roller (17) to which the powder is supplied from a vertical storage container (31) by a mechanical conveyor. The conveyor comprises a piston (32) which rises in steps within the container to convey the powder to an upper outlet opening over which a paddle wheel (34) rotates to transfer the powder to the roller (17). <IMAGE>

Description

SPECIFICATION Apparatus for depositing colour powder on a travelling strip of cigarette paper The invention relates to apparatus for depositing colour powder, preferably bronze powder, on prepared locations on a travelling strip of cigarette paper, having means for feeding the strip to be imprinted from a gum depositing device to a mechanical powder depositing device to which the colour powder may be supplied from a storage container by mechanical conveyor means.

The term "strip of cigarette paper" is understood to include also other strip-like wrapping materials for rod-like articles of the tobacco manipulating industry, for example wrapper strips for cigarillos or cigars or wrapper strips for rod-shaped filters.

Bronzing devices of the kind referred to above are used in the cigarette industry mainly for the purpose of providing the cigarette paper with an imprint before it is placed around the tobacco rod.

First the paper strip receives an imprint of a faintly coloured adhesive or a gum-like undercoat colour in the shape of the later final imprint. Thereupon bronze powder is deposited on the paper strip at the location of the imprint of adhesive, the bronze powder adhering to the location provided with adhesive. Excess bronze powder is removed again from the paper strip by means of a wiper roller, in particular from the locations which are not provided with the imprint of adhesive medium.

A bronzing apparatus is described in German Offenlegungsschrift 2 752 865, according to which bronze powder is removed from a lower outlet of a storage container by means of a worm conveyor and is fed to a depositing roller.

In the operation of such apparatus it was found that the feed flow of the bronze powder was interrupted very easily, so that the depositing roller and thereby the strip of cigarette paper were supplied with bronze powder at times in a defective manner or not at all, that is to say intermittently. These defects of the feed originate from the tendency of the bronze powder to stick together and to form bridges from the bronze particles. In this way in particular restrictions of the cross-section favour the interruption of the feed flow, particularly since solely gravity effects the lowering of the powder store to the lower outlet opening in the storage container of the kind referred to above. Additional mechanical loosening means which were inserted in the storage container produced merely a limited remedy and could not really solve the problem.

The invention has for its object the provision of apparatus by means of which an uninterrupted, accurately metered feed to the depositing means and thereby a uniform coating of the strip of cigarette paper is facilitated.

This problem is solved according to the invention, in that the conveyor means for supplying colour powder to the depositing means are constructed in the form of a storage container which is substantially vertically disposed and which is provided with lifter means for conveying the colour powder to an upper outlet opening, and in the form of a paddle wheel which is rotatable about a substantially vertical axis above the depositing means and which moves over at least a portion of the outlet opening of the storage container.

In this completely novel construction the colour powder is subjected to an enforced conveyance on its feed path from the storage container to the depositing means, in particular during the critical phase of the delivery from the storage container; this enforced conveyance prevents blockages and bridge formations of the colour powder and overcomes even possibly present restrictions or deflections of the feed path. Thereby a gap-free and uniform coating of the depositing means is ensured at any time which is necessary for a continuous bronze deposition on the strip of cigarette paper.

In order to be able to transfer to the strip of cigarette paper a sufficient, defined and locally limited quantity of the bronze powder by means of the depositing means, according to an advantageous embodiment of the invention the depositing means consists of a depositing roller which is provided with a grooved depositing zone in the grooving or roughening of which the bronze powder can be intercepted and retained.

In order to obtain in a simple manner a preliminary metering or division of the quantities of colour powder removed from the storage container, it is proposed furthermore that the paddle wheel is constructed in the form of a pocketed wheel divided by a plurality of walls.

For the purpose of enforced delivery of the colour powder from the storage container, according to an advantageous embodiment the lifter means comprise a piston which is movable upwards within the storage container which is of cylinder-shaped construction. It may be envisaged that the stroke movement of the piston is controlled by a separate driving means in accordance with the desired delivery quantity of the colour powder.

In contrast, the invention provides a drive which, in respect of control, may be integrated with the total drive of the associated machine with little expenditure; according to the proposal the drive consists in that the piston is movable upwards along a stationary spindle by the wall friction by means of the rotatably drivable storage container. According to an additional arrangement, a continuous stepwise supply, or division, respectively, and thereby metering of predetermined quantities of the bronze powder is obtained by the fact that the drive for the paddle wheel and the storage container is an intermittent uni-directional drive which is derived from the main drive of the machine.

For the purpose of determining and adjusting the optimum quantities of bronze powder, it is furthermore advantageous when the drive comprises a crank drive with an adjustable transmission ratio of its drive link rods. In this way the magnitude of the respective piston strokes which follow each other in a step-wise manner, as well as the corresponding respective swing angles of the paddle wheel are adjusted in the desired manner.

According to an additional embodiment the piston is associated with a two-stage end switch in the region of the outlet opening of the storage container; the said switch signals the closely impending end of the powder store, or stops the machine when the storage container has been completely emptied, respectively.

In order to retain the bronze powder which has been removed from the storage container and conveyed to the depositing roller by the paddle wheel, according to a further development the paddle wheel is associated with a bottom plate which comprises recesses in the region of the storage container and the depositing means.

The invention will be explained below in detail with reference to a constructional example illustrated in the drawings. There are shown in: Fig. 1 apparatus for depositing bronze powder on a strip of cigarette paper, in longitudinal section, Fig. 2 a side view of the apparatus, the partition walls of the casing having been omitted, and Fig. 3 a view from above on to the apparatus according to Fig. 2.

In the bronzing apparatus illustrated in Fig. 1 a strip 1 of cigarette paper to be imprinted is guided along a gum depositing device 2 for the purpose of depositing a gum image corresponding to the later imprint. The gum depositing device 2 comprises a gum container 3 from which gum 4 is removed by means of a removal roller 6 and supplied to a gum depositing roller 8 by means of a transfer roller 7; the gum depositing roller 8 is provided with projecting printing elements 9 for printing the gum image upon the cigarette paper strip 1. The gummed cigarette paper strip 1 is conveyed further from the gum depositing device 2 to a depositing roller 17 accommodated in a casing 16 by means of conveyor means in the form of guide rollers 11, 12, 13 and a guide plate 14 for the purpose of depositing bronze powder 18.After the deposition of the bronze powder 18 the cigarette paper strip 1 travels past a counter rotating wiper roller 1 9 which is arranged above the depositing roller 1 7 and which removes excess bronze powder 1 8 from the cigarette paper strip.

The depositing roller 1 7 and the wiper roller 1 9 are accommodated in a common depositing chamber 21 which is bounded by two dust removal chambers 24 and 26, respectively, which are separated off by intermediate walls 22, 23 and which are connected by suction conduits 27 and 28, respectively, to a blower 29 for the purpose of producing an underpressure.

In order to supply the depositing roller 1 7 with bronze powder 18, the conveyor means are provided which are illustrated in more detail in Figs. 2 and 3 and which comprise mainly a storage container 31 with a lifter means in the form of a piston 32 and a paddle wheel in the form of a pocketed wheel 34 divided by a plurality of walls 33, the piston being arranged in the said container.

At its upper end the vertically extending storage container 31 comprises an outlet opening 36 for the bronze powder 1 8 contained therein. A stationary spindle 37 extends from above into the storage container 31; the piston 32 is rotatable about the spindle 37 and thereby displaceable along the latter. The piston 32 is supported by means of an elastic sealing sleeve 38 on the inner cylinder wall of the storage container 31 with friction contact. The storage container 31 is rotatably inserted in a casing 39 and supports a toothed crown 41 for the purpose of step-wise rotary drive. A driving pinion 42 which engages into this toothed crown 41 is arranged at the lower end of a drive shaft 43 which additionally supports the pocketed wheel 34.At the opposite end, the drive shaft 43 supports a uni-directional drive 44 which is in operative connection with a crank drive 48 by means of a drive rod linkage consisting of a swing lever 46 and a coupling rod 47. The coupling rod 47 and the swing lever 46 are connected together by means of a slide block 49 displaceable at the swing lever 46, so that the transmission ratio of the drive rod linkage 46, 47 is adjustable; for this purpose the slide block 49 possesses an adjusting slot 51 and a clamping screw 52 inserted in the swing lever 46. The coupling rod 47 is pivotally mounted on a pin 53 which is inserted in the slide block 49. The crank drive 48 is a drive which is derived from the main drive (not illustrated in detail) of the associated cigarette rod machine.

Moreover, a displaceable end switch 56 extends from above into the storage container 31; the switch is biassed by a spring 54 and comprises two contacts 57 and 58 which are associated with counter-contacts 59 and 61, respectively, and the functioning of which will be described further below in detail.

A bottom plate 62 is arranged below the paddle wheel 34; in the region of the storage container 31 and the depositing roller 17 it is provided with recesses 63 and 64, respectively, for the purpose of removing bronze powder from the storage container 31 and delivering bronze powder 18 to the depositing roller 17, respectively.

The mode of operation of the apparatus is as follows: The continuously supplied cigarette paper strip 1 which is provided at intervals with a gum image corresponding to the later imprint in the gum depositing device 2 is continuously guided along the depositing roller 1 7. Simultaneously the storage container 31 is rotated in a step-wise manner by means of the continuously rotating crank drive 48 and the drive rod linkage 46, 47 in one direction (arrow 66), since the uni-directional drive 44 permits the free return movement of the drive rod linkage 46, 47. By means of the friction contact between the seal 38 of the piston 32 and the inner cylinder wall of the storage container 31 the piston 32 is forced to perform also every step wise rotation of the storage container 31.Thereby the piston 32 is moved upwards for a certain distance on the vertical spindle 37 at each rotary step. By each step-wise upward stroke of the piston 32 a corresponding quantity of the bronze powder 1 8 contained in the storage container 31 is lifted out of the upper outlet opening 36 of the storage container 31. The magnitude of the respective rotary angle of the storage container 31 or the respective piston stroke of the piston 32 respectively, and thereby the quantity of the bronze powder 1 8 lifted out of the storage container 31 is predetermined by the transmission ratio of the drive rod linkage 46, 47 adjusted by means of the slide block 49.

The pocketed wheel 34 which is securely mounted on the drive shaft 43 performs the same step-wise swing movements as the storage container 31, whereby the walls 33 of the pocketed wheel 34 which wipe over the storage container 31 strip off the bronze powder 18 which has been pressed out of the storage container 31, convey it away by means of the bottom member 62 arranged below the pocketed wheel 34 and let it fall down through the recess 64 of the bottom member 62 above the depositing roller 1 7 out of the pockets limited by the walls 33. The downward raining bronze powder 18 is intercepted by the depositing roller 1 7 the middle region of which is provided for this purpose with a roughened or grooved depositing zone 67 in which the required quantity of bronze powder 1 8 is accumulated.In order to relieve again the side zones of the depositing roller 1 7 which have necessarily also been sprayed, of the sprayed-ori bronze powder 18, a scraper 68 is provided. The bronze powder 1 8 which is located in the grooved depositing zone 67 is thereafter transferred to the cigarette paper strip 1 by the rotation of the depositing roller 17, whereby it remains adhering to the previously gummed locations on the cigarette paper strip 1. Subsequently the cigarette paper strip 1 passes a wiper roller 1 9 which removes again the bronze powder 1 8 which adheres to all undesired locations on the cigarette strip 1 as well as the excess of bronze powder deposited on the gummed imprint locations. This brushed-off excess travels again directly into the pocketed wheel 34 or to the depositing roller 1 7, respectively.The dust produced in the described coating process is sucked out of the dust removal chambers 24 and 26 which limit the depositing chamber 21, in order that the entire apparatus may be kept clean.

As the storage container 31 is progressively emptied, the piston 32 migrates slowly upwards, whereby finally it touches the end switch 56 which is raised so far that first the two contacts 57 and 59 are closed. The closure of the two contacts 57 and 59 causes a signal to be produced which indicates that the store of bronze powder 1 8 in the storage container 31 is coming to an end and on the other hand a fresh full storage container must be kept ready for the interchange. In case the signal is overlooked or the interchange in good time is omitted, the end switch 56 is moved to a second position by the piston 32 which continued to move upwards; in this second position the contacts 58 and 61 touch each other. This contact closure delivers a signal for the automatic stoppage of the entire machine.

The interchange of the empty storage container 31 for a full storage container is effected by simple actuation of a bayonet closure 69, for which purpose the storage container 31 is provided with a knurled grip 71.

Claims

1. Apparatus for depositing colour powder, preferably bronze powder, on prepared locations on a travelling strip of cigarette paper (as herein defined), comprising feed means for feeding the strip to be imprinted from a gum depositing device to a mechanical powder depositing device to which the colour powder may be supplied from a storage container by mechanical conveyor means, wherein the conveyor means for supplying colour powder to the depositing means comprise a substantially vertically disposed storage container which is provided with lifter means for the conveyance of the colour powder to an upper outlet opening, and a paddle wheel which is rotatable about a substantially vertical axis above the depositing means and which moves over at least a portion of the outlet opening of the storage container.

2. Apparatus as claimed in claim 1 , wherein the depositing means is a depositing roller which is provided with a grooved depositing zone.

3. Apparatus as claimed in claim 1 or 2, wherein the paddle wheel is a pocketed wheel divided by a plurality of walls.

4. Apparatus as claimed in any one of claims 1 to 3, wherein the lifter means comprise a piston which is movable upwards within the storage container which is of cylindrical construction.

5. Apparatus as claiined in any one of claims 1 to 4, wherein the piston is movable upwards along a stationary spindle as a result of rotation by the rotatably drivable storage container in frictional engagement therewith.

6. Apparatus as claimed in any one of claims 1 to 5, wherein the drive for the paddle wheel and the storage container is an intermittent unidirectional drive derived from the main drive of the machine.

7. Apparatus according to any one of claims 1 to 6, wherein the drive comprises a crank drive having an adjustable transmission ratio of its drive link rods.

8. Apparatus according to any one of claims 1 to 7, wherein the piston is associated with a twostage end switch in the region of the outlet opening of the storage container.

9. Apparatus according to any one of claims 1 to 8, wherein the paddle wheel is associated with a bottom plate which comprises recesses in the region of the storage container and the depositing means.

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10. Apparatus for depositing colour powder, preferably bronze powder, on prepared locations on a travelling strip of cigarette paper, substantially as herein described with reference to, and as illustrated in the accompanying drawings.