WO1999067137A1

WO1999067137A1 - A detector assembly

Info

Publication number: WO1999067137A1
Application number: PCT/IB1999/001163
Authority: WO
Inventors: Klaus Peter Lamm
Original assignee: Tobacco Research And Development Institute Limited
Priority date: 1998-06-22
Filing date: 1999-06-21
Publication date: 1999-12-29
Also published as: AU4284599A

Abstract

A detector assembly for detecting the presence of a bundle of cigarettes (50) in a cigarette transfer turret (10), which rotates between a rear fixed plate (24) and a front fixed plate (26), is provided. An array of triggering sensors (36) is mounted to the front plate (26) and includes an inner optical sensor (38), an intermediate optical sensor (40) and an outer optical sensor (42) for triggering, respectively, inner (30), intermediate (32) and outer (34) scanning sensors which are mounted against the rear plate (24). The turret plate (14) includes a series of equi-spaced profiled trigger inserts (44) which, as the entire turret assembly (10) rotates, triggers the triggering sensors (36) as the leading profile (46) of the trigger insert (44) traverses the array of triggering sensors (36). The resultant triggering signals from the triggering sensors (36) activate the respective corresponding scanning sensors which effectively cause the scanning cycle to commence. The scanning cycle terminates as soon as the trailing profile (48) of the insert (44) traverses the array of triggering sensors.

Description

A DETECTOR ASSEMBLY

BACKGROUND TO THE INVENTION

THIS invention relates to a detector assembly for detecting the presence of at least one article in a transfer device.

Once individual smoking articles such as cigarettes have been manufactured, they are collated into a specific configuration, such as a 7-6-7 "20 's" configuration, before being packaged. The manufactured cigarettes are conveyed into a hopper which terminates in an array of converging vanes. The cigarettes migrate downwardly through the evenly spaced gaps between the vanes in single rows, and a cigarette pusher at the base of the vanes pushes out the lowermost three rows of cigarettes into bundles which are received within a collating pocket. A number of such pockets form part of a rotary collating turret having a filling station and an opposed transfer station from where the collated bundles are transferred for wrapping.

It is essential that quality control standards are maintained during the transfer process. In particular, it is important to ensure that the correct number of cigarettes are bundled and collated. SUMMARY OF THE INVENTION

According to the invention there is provided a detector assembly for detecting the presence of a bundle of articles in a movable transfer device, the detector assembly comprising article detecting means, first and second triggering profiles arranged to move in concert with the transfer device past the article detecting means, and triggering sensor means responsive to the first and second triggering profiles for respectively initiating and terminating an article detecting cycle of the article detecting means.

In a preferred form of the invention, the first and second triggering profiles correspond, respectively, to the locations of leading and trailing articles in the bundle, which are determined by third and fourth profiles located towards leading and trailing article-receiving ends of the article transfer device.

Advantageously, the bundle of articles comprises a bundle of rod-like articles confined together in a predetermined configuration within at least one suitably profiled article-receiving pocket defined within the transfer device, the leading and trailing ends of the transfer device incorporating the third and fourth profiles, and the article sensing means being arranged to sense the integrity of the bundle of articles via exposed ends of the articles.

Conveniently, the detector assembly is carried on a turret assembly rotatable about a central axis and comprising a plurality of article transfer devices each defining article-receiving pockets arranged to rotate, stepwise, between an article filling station and an article eject station. Typically, at least one triggering sector defined on the turret by the first and second profiles and the central axis is similar to at least one sensing sector bounded by the third and fourth profiles.

Advantageously, the first and second profiles are located radially inwardly of the third and fourth profiles, and represent a radially scaled down facsimile of the first and second profiles.

Conveniently, the article-receiving pockets are equi-spaced, and a plurality of corresponding equi-spaced triggering profiles are distributed around the turret assembly.

In a preferred form of the invention, the triggering sensor means is angularly offset from the triggering profiles by the same degree as the article detecting means is angularly offset from the corresponding locations of the leading and trailing articles in the bundles as defined by the third and fourth profiles.

Typically, the article detecting means comprises a first array of optical sensors, and the triggering sensor means comprises a second array of optical sensors, with the first and second array having matching configurations.

The bundles of articles are conveniently arranged in three staggered rows, with the first array of optical sensors comprising three correspondingly staggered sensors, and the second array of optical sensors comprising three similarly staggered sensors.

In one form of the invention, the articles are smoking articles, the movable transfer device is a smoking article transfer turret carrying a plurality of equi- spaced pockets arranged to receive smoking articles in a 7:6:7 configuration. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a partly cut-away front view of a detector assembly of the invention;

Figure 2 shows part of the rear view of the detector assembly of Figure 1 ; and

Figure 3 shows a detailed cross-sectional side view of the triggering sensor means on the line 3-3 of Figure 1.

DESCRIPTION OF EMBODIMENTS

Referring first to Figure 1, a cigarette transfer turret 10 comprises seven equi- spaced transfer devices, five of which are visible at 12.1 to 12.5 respectively, each of which are bolted to a rotary turret plate 14 which rotates about a central shaft 16 defining an axis of rotation 16A. Each of the transfer devices includes a cigarette-receiving pocket 18 which is suitably profiled to receive a bundle of cigarettes 19 in a standard 7-6-7 row configuration associated with a 20' s pack. Each pocket 18 has suitably configured leading and trailing profiles 20 and 22 for maintaining the bundle in the correct 7-6-7 configuration.

The turret plate 14 rotates between a rear fixed plate 24 and a front fixed plate 26, with the gap between the front and rear plates being just sufficient to accommodate the turret assembly including the turret plate 14 and the transfer devices 12.1 to 12.5. A first scanning array of optical sensors 28 is mounted flush against the rear plate 24. The scanning array 28 includes, relative to the central axis 16A, an inner optical sensor 30 for scanning an inner row of 7 cigarettes, an intermediate sensor 32 for scanning an intermediate row of 6 cigarettes, and an outer sensor 34 for scanning an outer row of 7 cigarettes. A corresponding array of triggering sensors 36 is mounted to the front plate 26, with the array being flush with the inner surface of the front plate. The array includes a corresponding inner triggering optical sensor 38, an intermediate optical sensor 40 and an outer optical sensor 42 for triggering, respectively, the inner, intermediate and outer scanning sensors 30, 32 and 34.

Bolted to the turret plate 14 are a series of equi-spaced profiled inserts 44 each having a leading profile 46 and a trailing profile 48. The leading profile 46 is roughly representative of a scaled down version of the corresponding leading profile 20 of each pocket, and has, relative to the clockwise direction of rotation of the turret 10, an inner leading edge 46.1, a middle trailing edge 46.2 and an outer intermediate edge 46.3. The inner, intermediate and outer triggering sensors 38, 40 and 42 are radially offset from one another by exactly the same distance as the corresponding profile edges 46.1, 46.2 and 46.3.

The trailing edge of each profile 48 similarly includes an inner trailing edge

48.1, a middle leading edge 48.2 and an outer intermediate edge 48.3, with the profile 48 being a facsimile of a radially scaled down profile of the trailing edge 22 of each pocket.

During operation, the entire turret assembly rotates in a step-wise fashion between seven stations. The loose bundles of cigarettes are fed in at first and second filling stations positioned at 49.1 and 49.2 respectively by means of cigarette pushers (not visible) into the first and second transfer devices 12.1 and

12.2. In the Figure 1 view, the bundles of cigarettes are inserted with their smoking or soft ends exposed, with the opposed filter ends lying adjacent the rear plate 24. As the leading profile 46 of the trigger insert 44 traverses the array of triggering sensors 36, the individual sensors 38, 40 and 42 are simultaneously triggered by the corresponding respective leading edges 46.1, 46.2 and 46.3. The resultant triggering signals from the triggering sensors 38, 40 and 42 immediately activate the respective corresponding scanning sensors 30, 32 and 34 forming part of the scanning array 28. In the present embodiment, the triggering profile 46 forming part of the insert 44 which is located radially inwardly of the transfer device 12.4 will, on being triggered, effectively cause the scanning array 28 to commence the scanning cycle which scans the bundle of cigarettes 50 contained within the transfer device 12.2.

It will be appreciated that the scanning array 28 is radially offset from the centres of the leading cigarettes 50.1, 50.2 and 50.3 by exactly the same angle θl as the angle Θ2 the leading profile 46 of the insert is radially offset from the corresponding array of trigger sensors 36. As a result of this, and for the sake of clarity, the measuring cycle will now be described with reference both to the transfer device 12.4 and to the transfer device 12.2. It can clearly be seen by the produced radius 52 and the produced circumference 54 that scanning of the innermost row of cigarettes 56 will commence at point 58, corresponding to the midpoint or centre of the leading cigarette 50.3. Similarly, scanning of the outermost row 60 of cigarettes will commence at point 62, over the midpoint of cigarette 50.1, at the intersection of produced radius 64 and circumference 66. In the same way, scanning of the intermediate row 68 of cigarettes will commence at point 70, at the midpoint of cigarette 50.2, at the intersection of circumference 72 and radius 74.

As soon as the trailing profile 48 of the insert traverses the array of trigger sensors 36, this will have the effect of causing the measuring or scanning cycle of the scanning array 28 to terminate at points 76, 80 and 82 respectively. The rear profile 48 of the insert is effectively the mirror image of the profile represented by the array of trigger sensors 36, as a result of which the intermediate sensor 40 will be triggered before the outer sensor 42, which will in turn be triggered before the inner sensor 38. This will have the effect of causing the inner scanning sensor 30 to be the first to turn off at a point corresponding roughly to the midpoint of the trailing cigarette 50.4. This is followed by turn-off of the outer scanning sensor 34 at a point when it is directed onto the approximate midpoint of the outer trailing cigarette 50.5. The intermediate scanning sensor 32 then turns off as the midpoint of the inner trailing cigarette 50.6 passes by. As the scanning sensor 30 is proportionately closest to the trailing cigarette in the first row, the intermediate scanning sensor 32 is proportionately furthest from the trailing cigarette in the middle row and the scanning sensor 34 is proportionately between the first two sensors, the overall effect is that the staggered turning off of the sensors will occur at exactly the right position on the respective trailing cigarettes 50.6, 50.4 and 50.5 corresponding to the aforementioned points 76, 80 and 82.

The leading radius 74 and the corresponding trailing radius 75 define an inner triggering sector bounded by an arc 75.1 joining the leading edge 46.2 and the trailing edge 48.2. The corresponding sensing sector is defined by the leading radius 75.2, the trailing radius 75.3 and the arc 75.4 joining the points 50.4 and 50.1. Advancement of the triggering sector bounded by the leading radius 74, the trailing radius 75 and the arc 75.1 by an angle Θ2 will trigger the sensing sector bounded by radii 75.2 and 75.3 and arc 75.4 when that sector has moved through the identical angle θl, with optical triggering sensor 40 effectively triggering a scanning cycle by optical scanning sensor 32. Corresponding sets of triggering and sensing sectors exist for all of the rows in the seven pockets, as well as for all of the triggering profiles. This adds up to a total of 21 triggering sectors and 21 corresponding and similarly offset sensing sectors.

As is clear from Figure 2, the array 28 of scanning sensors is mounted within a housing which is bolted to the rear surface of the rear fixed plate 24. A cable gland 86 carrying an optical cable (not shown) provides individual optic transmit and receive fibres to each of the sensors 30, 32 and 34. The optical transmit fibres transmit light onto the white filter ends, and the receivers receive the reflected light. A missing cigarette in the row will immediately be picked up due to the reduction in the amplitude of the received signal arising from a gap or discontinuity. A central controller can then trigger an alarm and/or cause the machinery to halt so that the bundle in which there is a shortfall-induced gap can immediately be tracked. Alternatively, and preferably, the particular bundle of cigarettes in which there is a shortfall is tracked and is automatically ejected typically before but also possibly after packaging.

In Figure 3, a cross-sectional side view of the array of triggering sensors 36 is shown. The triggering sensors 36 are carried in a housing 88 which is bolted to the front plate 26 and which incorporates a cable gland 90 which feeds the triggering sensors 38, 40 and 42 with transmit and receive optical fibres, as was the case with the scanning sensor array.

An advantage of the invention is that it provides a relatively simple optomechanical arrangement for synchronizing measurement cycles to a high degree of accuracy without the need to use relatively expensive electronic shaft encoding equipment, which is not always reliable at high speeds and at radial increments of less than 1°. No drift problems arise, and in particular measuring problems associated with minor variations in speed of the turret, as there is complete synchronicity between the turret-mounted triggering and scanning sensors for every cycle measured. The absolute duration of the scanned signal is thus of no relevance. Rather, only the continuity of the signal needs to be monitored between two profile-determined points.

Claims

1 . A detector assembly for detecting the presence of a bundle of articles in a movable transfer device, the detector assembly comprising article detecting means, first and second triggering profiles arranged to move in concert with the transfer device past the article detecting means, and triggering sensor means responsive to the first and second triggering profiles for respectively initiating and terminating an article detecting cycle of the article detecting means.

2. A detector assembly according to claim 1 in which the first and second triggering profiles correspond, respectively, to the locations of leading and trailing articles in the bundle, which are determined by third and fourth profiles located towards leading and trailing article-receiving ends of the article transfer device.

3. A detector assembly according to claim 2 in which the bundle of articles comprises a bundle of rod-like articles confined together in a predetermined configuration within at least one suitably profiled article- receiving pocket defined within the transfer device, the leading and trailing ends of the transfer device incorporating the third and fourth profiles, and the article sensing means being arranged to sense the integrity of the bundle of articles via exposed ends of the articles.

4. A detector assembly according to claim 3 wherein the detector assembly is carried on a turret assembly rotatable about a central axis and comprising a plurality of article transfer devices each defining article- receiving pockets arranged to rotate, stepwise, between an article filling station and an article eject station.

5. A detector assembly according to claim 4 in which at least one triggering sector defined on the turret by the first and second profiles and the central axis is similar to at least one sensing sector bounded by the third and fourth profiles.

6. A detector assembly according to either one of claims 4 or 5 in which the first and second profiles are located radially inwardly of the third and fourth profiles, and represent a radially scaled down facsimile of the first and second profiles.

7. A detector assembly according to any one of the preceding claims 4 to 6 in which the article-receiving pockets are equi-spaced, and a plurality of corresponding equi-spaced triggering profiles are distributed around the turret assembly.

8. A detector assembly according to claim 7 in which the triggering sensor means is angularly offset from the triggering profiles by the same degree as the article detecting means is angularly offset from the corresponding locations of the leading and trailing articles in the bundles as defined by the third and fourth profiles.

9. A detector assembly according to any one of the preceding claims in which the article detecting means comprises a first array of optical sensors, and the triggering sensor means comprises a second array of optical sensors, with the first and second array having matching configurations.

10. A detector assembly according to claim 9 in which the bundles of articles are arranged in three staggered rows, with the first array of optical sensors comprising three correspondingly staggered sensors, and the second array of optical sensors comprising three similarly staggered sensors.

A detector assembly according to claim 10 in which the articles are smoking articles, the movable transfer device is a smoking article transfer turret carrying a plurality of equi-spaced pockets arranged to receive smoking articles in a 7:6:7 configuration.