WO1999067136A1

WO1999067136A1 - A pin-based detector for detecting the ends of articles in a bundle

Info

Publication number: WO1999067136A1
Application number: PCT/IB1999/001160
Authority: WO
Inventors: Klaus Peter Lamm
Original assignee: TOBACCO RESEARCH AND DEVELOPMENT INSTITUTE Ltd; Tobacco Research and Development Institute Pty Ltd
Current assignee: TOBACCO RESEARCH AND DEVELOPMENT INSTITUTE Ltd; Tobacco Research and Development Institute Pty Ltd
Priority date: 1998-06-22
Filing date: 1999-06-21
Publication date: 1999-12-29
Anticipated expiration: 2000-12-22
Also published as: AU4284499A

Abstract

A pin-based detector (10) for detecting the ends of a bundle of cigarettes (62) comprises a pin housing (12) and a plurality of pin assemblies (16) mounted slidably within the housing (12) and being movable between an extended position and a retracted position. The detector (10) further includes first sensing means for sensing if one of the pin assemblies (16) is not fully retracted by the extended cigarette ends (60) and second sensing means for sensing if one of the pin assemblies (16) is not extended when the cigarette ends (60) are withdrawn. The first and second sensing means comprise an optical transmitter (38) for generating an optical beam, an optical receiver (59) for receiving the beam and an optical beam path (50) defined between the optical transmitter (38) and receiver (59), which beam is broken or interrupted when at least one of the pins (18) is not in the fully extended or retracted positions.

Description

A PIN-BASED DETECTOR FOR DETECTING THE ENDS OF ARTICLES IN A BUNDLE

BACKGROUND TO THE INVENTION

THIS invention relates to a pin-based detector for detecting the ends of a bundle of articles.

Smoking articles such as cigarettes are typically collated into a specific configuration before being packaged. Once the cigarettes have been manufactured, they 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 columns, and a cigarette pusher at the base of the vanes pushes out the lowermost three cigarettes in each column in bundles which are typically in a 7-6-7 configuration. The bundles are pushed into a collating turret which present the cigarettes for wrapping in hinged lid or soft packs.

It is essential that quality control standards are maintained whilst the cigarettes are being bundled prior to wrapping. In particular, it is vital to ensure that the correct number of cigarettes are collated. It is also important to ensure that the integrity of the open ends of the cigarettes is maintained, in that they do not lose tobacco shreds.

An array of sprung pin-based detectors has in the past been used to sense the presence of the ends of the cigarettes. The cigarette ends are pressed up against the exposed ends of the reciprocable pins, causing the pins to move into a retracted position, with the fully retracted position being sensed by virtue of those pins which have been fully displaced completing an electrical circuit. Absent cigarettes, or cigarettes which are not properly filled, are identified by not completing the electrical circuit. The passage of current on completion of the electrical circuit may lead to oxidation at the contact points, and ultimately to individual pins fusing or becoming jammed in the fully retracted position, and thereby misleadingly mimicking the presence of an adequately filled cigarette under all conditions.

SUMMARY OF THE INVENTION

According to the invention there is provided a pin-based detector for detecting the ends of a bundle of articles, the detector comprising a pin housing, a plurality of pin assemblies mounted slidably and reciprocally within the housing, each of the pin assemblies being pushable by contact with the ends of the bundle of articles from an extended position to a retracted position, first sensing means for sensing if at least one of the pin assemblies is not fully retracted by the extended article ends and second sensing means for sensing if at least one of the pin assemblies is not extended when the article ends are withdrawn.

Preferably, the first and second sensing means are arranged to sense both the condition of the article ends and the presence or otherwise of the articles in the bundle.

Conveniently, the first sensing means comprises first optical transmitter means for generating a first optical beam, first optical receiver means for receiving the beam and a first optical beam path defined between the optical transmitter and receiver means, which beam is broken or interrupted when at least one of the pins is not in a fully extended position.

Typically, the first optical path is defined by a plurality of first waisted portions or indents in each pin, in combination with a first series of interleading apertures defined in the pin housing, the apertures and waisted portions being aligned to define the first optical path when all of the pins are fully extended.

Advantageously, the second sensing means comprises second optical transmitter means for generating a second optical beam, second optical receiver means for receiving the beam and a second optical beam path defined between the optical transmitter and receiver means, which beam is broken or interrupted when at least one of the pins is not in a fully retracted position.

Typically, the second optical path is defined by a plurality of second waisted portions or indents in each pin, in combination with a second series of interleading apertures defined in the pin housing, the apertures and waisted portions being aligned to define the second optical path when all of the pins are fully retracted.

Advantageously, each of the pin assemblies include biasing springs for biasing the pins to the extended position, the biasing springs being in the form of precision compression coil springs having a predetermined resilience.

Conveniently, a free end of each of the pins terminate in a head sized to receive the end of an article, with the pin inertia, the predetermined spring resilience, and the width of the waisted portions being arranged to sense the condition of the article end within acceptable quality control-based limits. By the term "acceptable quality control-based limits", is meant that the condition of the article ends as sensed by the first sensing means is within the quality control standards set for that particular type or group of articles during manufacture thereof.

Typically, the bundle of articles is arranged in at least two rows, with the plurality of pin assemblies being arranged in corresponding rows, each of the rows being provided with first and second sensing means.

In one form of the invention, the articles are smoking articles, with the first and second sensing means and the pin assemblies in combination being arranged to cause the condition of the smoking end of each cigarette in the bundle, including cigarette filling and density.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a partly cut away top plan view of a pin-based detector of the invention in an extended position;

Figure 1A shows a partly schematic cross-sectional side view on the line 1A-1A of Figure 1;

Figure IB shows a partly cut-away top plan view of the pin-based detector of Figure 1 in the retracted position.

Figure 2 shows a front view of the pin-based detector of Figure 1 ; and

Figure 3 shows a side view of the detector. DESCRIPTION OF EMBODIMENTS

Referring first to Figure 1, a pin-based detector of the invention 10 comprises a pin housing 12 formed with an array of stepped round cylindrical pin apertures 14 within which a plurality of pin assemblies 16 are slidingly movable. Each of the pin assemblies 16 comprises a round cylindrical pin body 18 from which an expanded pin head 20 extends on a narrowed shaft 21. The opposite end of the pin body is formed with a spring-locating stem 22 which locates and extends through a coil spring 24, with an innermost end of the coil spring 24 locating against a spring seat 26 and the outermost end of each coil spring locating against a shoulder 28 from which the stem 22 projects. Each of the pin bodies is formed with an inner waisted portion 30 and an outer waisted portion 32. An apertured front wall 33 is carried on the front of the housing, with the pin heads 20 and shafts 21 projecting through the array of apertures 33.1.

An optical transmitter holder 34 is pivoted on an axle 36 extending through the pin housing 12. The optical transmitter holder 34 carries a first three-deep array of optical transmitters 38 and a second three-deep array of optical transmitters 40, each of which include respective optic fibres 42 and 44 which terminate in respective collimating lenses 46 and 48.

As is clear from Figure 1A, the collimating lens 48 is arranged to transmit an optical beam through a path 50 defined by the waisted portions 32 in conjunction with aligned interleading apertures 52 passing through the pin housing 12. A receiving lens 54 is located at the opposite end of the path 52, and forms part of a second array of optical receivers indicated in broken outline at 56 which is carried on an optical receiver holder 58. The optical receiver holder 58 also carries a first three-deep array of optical receivers 59 cooperating with the array of optical transmitters 38.

When all of the pins are in the extended position illustrated in Figure 1 , the receiving lens 54, together with the two underlying receiving lenses of the second array of optical receivers 56, will receive a signal from the transmitting lens 48 and the corresponding underlying lenses of the second array of optical transmitters 40. This serves as an effective indication that none of the pin assemblies are jammed in a retracted position.

During a testing cycle, the pin heads are brought up against the smoking ends 60 of a freshly collated bundle of cigarettes, one row of which is indicated at 62. The entire pin-based detector assembly, which is mounted on a central mounting arm (not shown) by means of an array of mounting bolts 64, is moved forwards in the direction of arrow 66 so that the fixed smoking ends 60 of the cigarettes serve to depress the pin assemblies into the fully retracted Figure IB position. When all the pins are in the fully retracted Figure IB position, the waisted portions 30, in conjunction with interleading apertures 67 in the pin housing, which are similar to the interleading apertures 52, provide paths for the optical beams between the three transmitting lenses 46 and the two underlying lenses of the first array of optical transmitters 38 and the receiving lens 68 and the two underlying lenses of the first array of optical receivers 59.

If one of the pins is not depressed properly, then it will effectively block the optical path and the signal will not be received at the receiving lenses 68. If a pin remains in the fully extended Figure 1 position, this clearly indicates an absent cigarette. Partial retraction of a pin arises from the absence of tobacco particles at the cigarette ends 60, which are not effective to push the particular pin into the fully retracted Figure IB position. The diameter of the pin heads 20 together with the relatively low mass of the pins, which are formed from titanium, and the characteristics of the springs 24, are such that the pins are fully depressed into the Figure IB position by a correctly filled cigarette. In the specific embodiment, the pin heads have a diameter of 5mm, and the springs have a working length of 6.5mm, and a force varying from an extended working length of 0.65N to a retracted or compressed working length of 1.17N. The length of the waisted portions (around 3mm) is sufficient to allow for acceptable minor deviations in cigarette end filling and density.

The inner pin housing 12 locates within an outer housing 72. It is clear from Figures 2 and 3 that the pins are arranged in a 7-6-7 configuration in three rows 74, 76 and 78, corresponding to the standard array of cigarettes in a "30's" pack. Naturally, the configuration is variable depending on the format of the collated bundle of cigarettes.

In the event of an optical signal in any of the rows not being sensed in the retracted or extended positions, the offending bundle of cigarettes is tagged or clocked and is subsequently ejected preferably prior to but also optionally after packaging.

It will be appreciated that the pin-based detector of the invention is not confined to detecting correctly filled and positioned cigarette ends, but may also be used to detect the end of any other typically rod-like articles which are subjected to a uniform bundling operation prior to packaging. The particular advantage of the pin-based detector of the invention is that it may be used simultaneously to check certain quality aspects (such as adequate filling and density) of rod-like articles, as well as simultaneously conducting an audit on the correct number and positioning of bundled articles.

Claims

1. A pin-based detector for detecting the ends of a bundle of articles, the detector comprising a pin housing, a plurality of pin assemblies mounted slidably and reciprocally within the housing, each of the pin assemblies being pushable by contact with the ends of the bundle of articles from an extended position to a retracted position, first sensing means for sensing if at least one of the pin assemblies is not fully retracted by the extended article ends and second sensing means for sensing if at least one of the pin assemblies is not extended when the article ends are withdrawn.

2. A pin-based detector according to claim 1 in which the first and second sensing means are arranged to sense both the condition of the article ends and the presence or otherwise of the articles in the bundle.

3. A pin-based detector according to either one of the preceding claims in which the first sensing means comprises first optical transmitter means for generating a first optical beam, first optical receiver means for receiving the beam and a first optical beam path defined between the optical transmitter and receiver means, which beam is broken or interrupted when at least one of the pins is not in a fully extended position.

4. A pin-based detector according to claim 3 in which the first optical path is defined by a plurality of first waisted portions or indents in each pin, in combination with a first series of interleading apertures defined in the pin housing, the apertures and waisted portions being aligned to define the first optical path when all of the pins are fully extended.

5. A pin-based detector according to either one of the preceding claims 3 or 4 in which the second sensing means comprises second optical transmitter means for generating a second optical beam, second optical receiver means for receiving the beam and a second optical beam path defined between the optical transmitter and receiver means, which beam is broken or interrupted when at least one of the pins is not in a fully retracted position.

6. A pin-based detector according to claim 5 in which the second optical path is defined by a plurality of second waisted portions or indents in each pin, in combination with a second series of interleading apertures defined in the pin housing, the apertures and waisted portions being aligned to define the second optical path when all of the pins are fully retracted.

7. A pin-based detector according to any one of the preceding claims in which each of the pin assemblies include biasing springs for biasing the pins to the extended position, the biasing springs being in the form of precision compression coil springs having a predetermined resilience.

8. A pin-based detector according to claim 7 in which a free end of each of the pins terminate in a head sized to receive the end of an article, with the pin inertia, the predetermined spring resilience, and the width of the waisted portions being arranged to sense the condition of the article end within acceptable quality control-based limits.

9. A pin-based detector according to any one of the preceding claims in which the bundle of articles is arranged in at least two rows, with the plurality of pin assemblies being arranged in corresponding rows, each of the rows being provided with first and second sensing means.

10. A pin-based detector according to any one of the preceding claims in which the articles are smoking articles, with the first and second sensing means and the pin assemblies in combination being arranged to cause the condition of the smoking end of each cigarette in the bundle, including cigarette filling and density.