Method and apparatus for testing cigarettes or the like

Filter cigarettes of double unit length are tested in the filter tipping machine in a selected portion of their normal path of sidewise movement toward the discharge end of the machine. In such selected portion, successive filter cigarettes are arrested and simultaneously rotated about their respective axes. During rotation, a first optoelectrical unit scans the wrappers of the cigarettes for the presence of protuberances, and a second optoelectrical unit scans the wrappers for the presence of open seams, holes, frayed ends and/or smudges. On detection of defects, the transducers of the respective units generate signals which are used to segregate the respective cigarettes from other cigarettes.

BACKGROUND OF THE INVENTION 
The present invention relates to improvements in testing of rod-shaped 
articles which constitute or form part of smokers' products. More 
particularly, the invention relates to a novel and improvement method and 
to a novel and improved apparatus for testing successive plain or filter 
tipped cigarettes, cigars or cigarillos, cheroots, filter rod sections or 
similar rod-like articles (which may consist of natural or reconstituted 
tobacco, tobacco substitutes, filamentary and/or granular filter material 
and/or a combination of such substances) while the articles are in the 
process of moving or about to move sideways, i.e., substantially at right 
angles to their respective axes. 
It is well known to test rod-shaped articles which constitute or form part 
of smokers' products (for the sake of convenience, such articles will be 
referred to as cigarettes with the understanding, however, that the 
invention can be practiced with equal advantage in connection with all or 
nearly all types of rod-like smokers'products) before the cirgarettes are 
introduced into packets, boxes or other types of containers for storage or 
for sale to customers. The testing is intended to uncover the presence of 
wrappers which exhibit holes, unsatisfactory seams, frayed ends and/or a 
combination of two or more such defects. As a rule, the testing operation 
is carried out pneumatically, for example, by establishing a pressure 
differential between the interior and the exterior of the wrappers of 
successive cigarettes. If a wrapper exhibits one or more defects of the 
above outlined character, monitoring of the pressure within or around the 
defective wrapper will reveal the presence of such defect or defects, and 
the corresponding cigarette is thereupon segregated from the remaining 
(satisfactory) cigarettes. The arrangement may be such that the pneumatic 
testing apparatus generates a signal when the permeability of the wrapper 
of a cigarette is excessive and/or insufficient, and the signal is used 
for automatic segregation of the corresponding cigarette. Reference may be 
had to commonly owned U.S. Pat. Nos. 3,783,677 and 3,962,906 respectively 
granted Jan. 8, 1974 and June 15, 1976 which show a few recent types of 
pneumatic testing apparatus for cigarettes or the like. 
A drawback of pneumatic testing apparatus is that they are incapable of 
detecting each and every defect in or on the wrapper of a cigarette or the 
like. For example, a pneumatic testing apparatus will fail to detect a 
hole which happens to be plugged, either entirely or in part, by a 
fragment of tobacco. The hole can be large enough to be readily detectable 
with the naked eye; nevertheless, even a highly sensitive pneumatic 
testing apparatus is unlikely to detect such hole if the latter is 
accidentally sealed by a fragment of a tobacco rib or the like. 
A pneumatic testing apparatus is further unlikely to ascertain the presence 
of certain defects which do not unduly affect the quality of cigarettes 
but detract from the eye-pleasing appearance of such smokers' products. 
For example, pneumatic testing apparatus will not detect the presence of a 
tobacco crumb between the overlapping edge portions of cigarette paper 
which forms the wrapper, i.e., the presence of a crumb in the seam of the 
wrapper even though such crumb causes pronounced deformation (bulging) of 
the corresponding portion of the seam. 
Another defect found in cigarettes, especially filter cigarettes, which is 
not likely to be detected by resorting to a pneumatic testing apparatus is 
the presence of so-called lips or flags on the convoluted uniting bands 
which connect plain cigarettes with filter plugs. As a rule, a filter 
tipping machine makes filter cigarettes of double unit length; each such 
cigarette is thereupon severed midway between its ends to yield two filter 
cigarettes of unit length. The cut is made centrally across the convoluted 
(tubular) uniting band which is used to connect a filter plug of double 
unit length with two plain cigarettes of unit length. If the uniting band 
is not applied in an optimum position, it is likely that one of its edges 
(namely, one of those edges which extends in parallelism with the axis of 
the filter cigarette of double unit length) will project beyond the 
confined filter plug and will form a lip which is detectable by the smoker 
and is likely to lead to detachment of the filter plug from the plain 
cigarette or cigarettes. The presence of the just discussed flags or lips 
is often caused by unsatisfactory coating of one side of the uniting band 
with a suitable adhesive. 
British Pat. No. 1,028,372 discloses an apparatus for optically scanning 
the wrappers of cigarettes or the like. The apparatus of this patent 
embodies means for withdrawing successive articles to be tested from their 
normal path, for inserting successively withdrawn articles between two 
rotating drums, and for optically scanning the articles between the 
rotating drums. The patented apparatus exhibits several serious drawbacks, 
especially as concerns the complexity of the withdrawing means. Moreover, 
the two rotating drums perform no function other than to rotate the 
articles during optical scanning, and the apparatus occupies a substantial 
amount of space mainly because it utilizes several components (such as the 
two drums and the withdrawing means) which serve no other purpose but to 
allow for optical scanning of articles. Therefore, the just discussed 
patented apparatus failed to gain widespread acceptance in the industry. 
U.S. Pat. No. 3,854,587 discloses a ring-shaped optical testing head for a 
continuous wrapped tobacco filler which is caused to pass axially through 
the testing head. During such transport of the wrappecd filler, the 
optical components on the testing head scan the wrapper of the filler and 
generate signals which, when indicative of a defective wrapper portion, 
are used to segregate the corresponding portions of the filler from the 
remaining (satisfactory) portions. A drawback of such optical scanning 
apparatus is that the testing operation is carried out too early, i.e., 
prior to subdivision of the wrapped filler into discrete rod-shaped 
articles, such as cigarettes or the like. Therefore, and in order to 
insure segregation of all defective articles (e.g. filter cigarettes of 
unit length), the apparatus of U.S. Pat. No. 3,854,587 must be followed by 
a second testing apparatus or the testing operation is unreliable because 
numerous discrete defective rod-shaped articles are likely to remain 
undetected prior to insertion into packets or the like. 
OBJECTS AND SUMMARY OF THE INVENTION 
An object of the invention is to provide a novel and improved method of 
optically testing cigarettes or like rod-shaped articles in such a way 
that the articles to be tested need not be withdrawn from their normal 
path, i.e., from the path along which the articles would advance in the 
absence of any testing of their wrappers. 
Another object of the invention is to provide a method which insures 
segregation of all defective rod-shaped articles in a time- and 
space-saving manner. 
A further of the invention is to provide a method which can be resorted to 
for reliable detection of all types of defects in or on the wrappers of 
cigarettes or the like, including such defects which are likely to remain 
undetected by a pneumatic testing apparatus. 
An additional object of the invention is to provide a simple and reliable 
method which insures accurate scanning of each and every portion of the 
wrapper of each of a continuous series of plain or filter tipped 
cigarettes or other rod-shaped articles which constitute or form part of 
smokers' products. 
Another object of the invention is to provide a novel and improved 
apparatus for the practice of the above-outlined method. 
A further object of the invention is to construct and assemble the 
apparatus in such a way that each and every rod-shaped article can be 
scanned during transport along its normal path, ie., along the path which 
would be acceptable in the absence of any optical testing. 
Another object of the invention is to provide the apparatus with novel and 
improved means which insures that the scanning of wrappers of rod-shaped 
articles for the presence or absence of defects invariably begins and 
takes place while the respective article is in an optimum condition and/or 
position for testing of its wrapper. 
One feature of the invention resides in the provision of a method of 
testing successive rod-shaped articles (such as plain cigarettes, filter 
cigarettes or the like) which constitute or form part of smokers' 
products. The method comprises the steps of conveying the articles 
seriatim sideways along a predetermined path, decelerating successive 
articles (for example, from a constant speed to zero speed) in a 
predetermined portion of the path and rotating the declerated articles 
about their respective axes, and electrooptically scanning each article in 
the course of the corresponding rotating step. 
The scanning step preferably comprises electrooptically monitoring the 
condition of tubular wrappers of successive articles (in the case of a 
filter cigarette of double unit length, the wrapper includes the tubular 
wrappers of the two plain cigarettes, the tubular wrapper (if any) of the 
filter plug of double unit length between the two plain cigarettes, and 
the convoluted adhesive-coated uniting band which surrounds the filter 
plug and connects the latter to the adjacent ends of the two plain 
cigarettes). 
As mentioned above, the decelerating step preferably includes interrupting 
the sidewise movement of that article which is about to be scanned, i.e., 
reducing the speed of sidewise movement of the article to zero. The 
rotating step preferably includes turning the decelerated articles through 
approximately or exactly 360 degrees to thus insure that each and every 
portion of the wrapper of each article can be optically scanned before the 
article leaves the testing station, i.e., the aforementioned portion of 
the path along which the articles are conveyed. 
The scanning step may comprise directing at least one beam of radiation 
(e.g., light) substantially radially against the rotating article in the 
predetermined portion of the path and evaluating the beam subsequent to 
impingement upon the article. Such evaluating can involve directing the 
beam which is reflected by the wrapper of an article against one or more 
photoelectronic tranducers whose signals are used to segregate certain 
articles from the remaining articles if the characteristics of 
corresponding signals are indicative of defective articles. 
The scanning step may also include (in addition to or as a substitute for 
the just discussed scanning step) directing at least one beam of radiation 
(e.g., light) in substantial parallelism with the axis of the rotating 
article so that the beam normally impinges upon a photoelectronic 
transducer. In the absence of impingement, the tested article is likely to 
be defective, and the signal at the output of the transducer is then used 
to effect segregation of such article from the other (satisfactory) 
articles. 
The method preferably further comprises the step of initiating the scanning 
step in response to start of the rotating step. This insures that an 
article is invariably scanned while it rotates about its own axis so that 
the optoelectric or optoelectronic scanning means can monitor the entire 
external surface of the respective wrapper. 
The novel features which are considered as characteristic of the invention 
are set forth in particular in the appended claims. The improved apparatus 
itself, however, both as to its construction and its mode of operation, 
together with additional features and advantages thereof, will be best 
understood upon perusal of the following detailed description of certain 
specific embodiments with reference to the accompanying drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows a filter tipping machine of the type known as MAX S (produced 
by the assignee of the present application). This machine is directly 
coupled to a cigarette maker so that it receives pairs of plain cigarettes 
PC (see FIG. 3) of unit length. The frame F of the filter tipping machine 
supports a rotary drum-shaped row-forming conveyor 1 which forms part of 
the cigarette maker and has peripheral flutes for plain cigarettes of unit 
length. The arrangement is such that the cigarette maker feeds a discrete 
plain cigarette PC into each flute of the conveyor 1 and that the plain 
cigarettes form two rows wherein the cigarettes move sideways. The 
cigarettes of one row are held in the oddly numbered flutes and are nearer 
to one axial end of the conveyor 1, and the cigarettes of the other row are 
held in the evenly numbered flutes and are nearer to the other axial end of 
the conveyor 1. 
The filter tipping machine comprises two rotary drum-shaped aligning 
conveyors 2 each of which serves to deliver plin cigarettes PC of a 
discrete row from the row forming conveyor 1 to a transfer station T1 
where the cigarettes PC enter successive flutes of a rotary drum-shaped 
assembly conveyor 3. The conveyors 2 are driven at different speeds and/or 
transport the cigarettes PC of the respective rows through different 
distances so that each flute of the assembly conveyor 3 which reaches the 
transfer station T1 receives two coaxial plain cigarettes PC of unit 
length. The width of the gap between two plain cigarettes PC in a flute 
which reaches the station T1 at least equals and normally at least 
slightly exceeds the length of a filter rod section or filter plug FP (see 
FIG. 3) of double unit length. 
The frame F further supports a magazine 4 for a supply of filter rod 
sections of six times unit length. The outlet of the magazine 4 receives a 
portion of a rotary drum-shaped severing conveyor 6 which is formed with 
peripheral flutes to transport discrete filter rod sections of six times 
unit length past two rotary disk-shaped knives 7. The knives 7 are spaced 
apart from each other, as considered in the axial and circumferential 
direction of the severing conveyor 6, and cooperate with the latter to 
subdivide each filter rod section of six times unit length into a set of 
three coaxial filter plugs FP of double unit length. Successive sets of 
filter plugs FP are transferred onto a rotary staggering conveyor 8 having 
three disk-shaped rotary portions, each of which receives and advances one 
filter plug FP of each set. The three portions rotate at different speeds 
and/or transport the respective filter plugs FP through different 
distances so that each set of originally coaxial plugs FP is converted 
into a row of three axially staggered filter plugs which are disposed one 
behind the other, as considered in the circumferential direction of the 
staggering conveyor 8. The portions of the conveyor 8 deliver discrete 
filter plugs FP into successive flutes of a rotary drum-shaped shuffling 
conveyor 9 which cooperates with two stationary cams 9A to convert the 
axially staggered filter plugs FP into a single row wherein each preceding 
plug is in exact register with the next-following plug. The shuffling 
conveyor 9 delivers successive filter plugs FP of the single row into 
successive peripheral flutes of a rotary drum-shaped accelerating conveyor 
11 which inserts such filter plugs into successive flutes of the assembly 
conveyor 3 at a transfer station T2 preceding the transfer station T1, as 
considered in the direction of rotation of the conveyor 3. The filter 
plugs FP are inserted in such a way that, once the respective flute of the 
assembly conveyor 3 reaches the transfer station T1, each freshly inserted 
filter plug is flanked by two coaxial plain cigarettes PC of unit length. 
In other words, each of those flutes of the assembly conveyor 3 which 
advance beyond the transfer station T1 contains a group of three coaxial 
rod-shaped articles including a centrally located filter plug FP of double 
unit length and two plain cigarettes PC of unit length. Such groups are 
caused to advance between two stationary cams 3A which cause the plain 
cigarettes PC to move axially toward and into contact with the adjacent 
ends of the respective filter plug FP, i.e., the groups are shortened or 
condensed prior to entering the flutes of a rotary drum-shaped transfer 
conveyor 12. 
The frame F also supports a spindle 14A for a reel or bobbin 14 of flexible 
wrapping material 13 (e.g., a web of cigarette paper or imitation cork) 
which is used for the making of uniting bands UB, i.e., of short square or 
rectangular patches of wrapping material which are employed to connect the 
filter plugs FP of successive groups with the respective plain cigarettes 
PC so that each group constitutes a filter cigarette 37 of double unit 
length. The web 13 is drawn off the reel 14 by a pair of rotary advancing 
rolls 16 and is caused to move past and to engage the relatively sharp 
edge of a so-called curling device 17, e.g., a device of the type 
disclosed in commonly owned U.S. Pat. No. 3,962,957 granted June 15, 1957, 
to Alfred Hinzmann. The purpose of the curling device 17 is to equalize 
internal stresses in the web 13 so that the latter can be readily 
converted into a succession of uniting bands each capable of establishing 
an airtight seal between a filter plug FP and the respective plain 
cigarettes PC. 
The web 13 thereupon advances along a paster 18 which serves to coat one 
side of the web with a suitable adhesive paste before the web reaches a 
rotary suction drum 19. The cylindrical peripheral surface of the drum 19 
is formed with ports (not shown) which surround and communicate with a 
suction chamber so that the peripheral surface of the drum 19 attracts the 
leader of the web 13 and causes such leader to advance past a rotary 
carrier 21 for knives 21A serving to sever the leader of the web 13 at 
regular intervals and to thereby form a succession of discrete uniting 
bands UB each having one of its sides coated with adhesive supplied by the 
paster 18. The peripheral speed of the drum 19 preferably somewhat exceeds 
the speed of lengthwise movement of the web 13 so that successive uniting 
bands UB are automatically separated from each other and are attached to 
successive groups of rod-shaped articles on the transfer conveyor 12. The 
mode of attachment is preferably such that each uniting band UB adheres to 
the corresponding filter plug FP and to the inner end portions of the 
respective plain cigarettes PC. The properly attached uniting bands UB are 
preferably tangential or nearly tangential to the corresponding groups of 
articles on the transfer conveyor 12, and each such group (with a uniting 
band adhering thereto) is thereupon transferred onto a rotary drum-shaped 
wrapping conveyor 22 which cooperates with a stationary or mobile rolling 
device 23 to cause each group to rotate about its own axis and to thus 
convert the respective uniting band UB into a tube (see FIG. 3) which 
sealingly surrounds the respective filter plug FP and the adjacent inner 
end portions of the corresponding plain cigarettes PC. Thus, the parts 22, 
23 cooperate to convert each group and a uniting band into a filter 
cigarette 37 of double unit length. The manner in which the conveyor 22 
cooperates with a stationary or mobile rolling device to convert uniting 
bands UB into tubes is disclosed in commonly owned U.S. Pat. No. 3,527,234 
to Alfred Hinzmann, granted Sept. 8, 1970. 
Successive filter cigarettes 37 of double unit length are transferred onto 
a rotary drum-shaped drying conveyor 24 which is heated from within and 
serves to promote setting of the adhesive applied by the paster 18. In 
addition, the conveyor 24 forms part of the improved testing apparatus and 
defines a predetermined portion of the elongated path along which the 
cigarettes 37 are moved sideways through the filter tipping machine of 
FIG. 1. 
The conveyor 24 delivers successive filter cigarettes 37 to a rotary 
drum-shaped severing conveyor 26 which cooperates with a rotary 
disk-shaped knife 26A to sever each filter cigarette 37 midway between its 
ends (along the broken line BL shown in FIG. 3) so that each cigarette 37 
yields two filter cigarettes of unit length. As mentioned above, the 
conveyor 24 forms part of the improved testing apparatus. Articles (i.e., 
filter cigarettes 37 or filter cigarettes of unit length) which are found 
to be defective during travel with the conveyor 24 are or can be 
segregated from other (satisfactory) articles during transport with the 
severing conveyor 26. 
Since the cigarettes 37 are severed midway across their convoluted uniting 
bands UB, the filter plugs (of unit length) of each pair of filter 
cigarettes of unit length on the severing conveyor 26 are adjacent to each 
other. This is undesirable since, when in a packet, the filter cigarettes 
are normally stored in such a way that all filter tips face in the same 
direction. Therefore, the filter tipping machine of FIG. 1 further 
comprises a so-called turn-around or inverting device 29 which turns one 
filter cigarette of each pair through 180 degrees before the filter 
cigarettes of unit length are conveyed on to a packing machine or into 
storage. The turn-around device 29 is of the type disclosed in commonly 
owned U.S. Pat. No. 3,583,546 granted June 8, 1971 to Gerhard Koop, and 
comprises a first rotary drum-shaped conveyor 27 which receives pairs of 
filter cigarettes of unit length from the severing conveyor 26. One filter 
cigarette of each pair is transferred onto a second rotary drum-shaped 
conveyor 27A of the device 29 and the remaining filter cigarettes are 
transferred from the conveyor 27 into alternate peripheral flutes of a 
third rotary drum-shaped conveyor 28. The device 29 further comprises a 
set of orbiting arms 29A which remove filter cigarettes of unit length 
from the flutes of the conveyor 27A, turn such filter cigarettes through 
180 degrees, and insert the inverted filter cigarettes into successive 
flutes of a fourth rotary drum-shaped conveyor 28A of the turn-around 
device 29. The conveyor 28A inserts the inverted filter cigarettes of unit 
length into the empty flutes of the conveyor 28, preferably in such a way 
that the inverted and non-inverted cigarettes form a single row which is 
transferred into the peripheral flutes of a rotary drum-shaped testing 
conveyor 31. The latter serves to test the quality of the 
tobacco-containing ends of successive filter cigarettes of unit length and 
delivers the tested cigarettes to a rotary drum-shaped intermediate 
conveyor 32. The conveyor 32 can also serve as a part of means for 
ejecting filter cigarettes which have been found to be defective during 
testing on the conveyor 31. Satisfactory filter cigarettes of unit length 
are transferred onto the upper reach of an endless belt or band conveyor 
36 which delivers the cigarettes to the hopper of a packing machine, to a 
pneumatic sender, to storage or to a so-called mass flow linkup equipment, 
e.g., to equipment known as Resy and manufactured by the assignee of the 
present application. The conveyor 36 is trained over pulleys 34. The 
illustrated pulley 34 cooperates with a braking drum 33 which is mounted 
above the upper reach of the conveyor 36. 
The frame F further supports a second spindle 114A for a fresh reel 114 
which contains a supply of convoluted web material 113. The leader of the 
fresh web 113 is located at a splicing station SPL and is ready to be 
attached to the running web 13 as soon as the supply of web 13 on the 
expiring reel 14 is reduced to a predetermined value. Reference may be had 
to commonly owned U.S. Pat. No. 3,730,811 granted May 1, 1973, to 
Hans-Joachim Wendt which describes a splicing device capable of being used 
at the station SPL to attach the trailing portion of a running web to the 
leader of a fresh web. 
All or nearly all rotary or otherwise movable components of the filter 
tipping machine receive torque or other motion from a main prime mover PM 
which preferably also drives the mobile parts of the aforediscussed 
cigarette maker including the row forming conveyor 1. 
The improved testing apparatus comprises the aforementioned drying conveyor 
24 (see also FIG. 2) and a roller-shaped rotary element 42 which is 
adjacent to but spaced apart from the conveyor 24. Each freshly formed 
filter cigarette 37 of double unit length is automatically transferred 
from the conveyor 22 onto the conveyor 24 and is caused to move toward the 
rotary element 42 to thereby begin to rotate about its own axis while one 
or more optoelectrical units scan its wrapper. Simultaneous engagement of 
the wrapper of a cigarette 37 by the conveyor 24 and rotary element 42 
entails a deceleration of such cigarette, preferably to zero speed (as 
concerns the sidewise movement of the cigarette in a direction from the 
conveyor 22 toward the severing conveyor 26). This is advisable in order 
to insure that the optoelectrical scanning unit or units need not move 
back and forth along that portion of the path of cigarettes 37 wherein the 
cigarettes are caused to rotate about their respective axes. 
The periphery of the conveyor 24 is formed with several (e.g., eight) 
convex peripheral surfaces or facets 39 each of which is flanked by two 
flutes 38A, 38B extending in parallelism with the axis of the conveyor 24. 
The transfer of cigarettes 37 from the conveyor 22 onto the conveyor 24 
takes place in such a way that the cigarettes are delivered into 
successive flutes 38A. Each of the flutes 38A, 38B has one or more suction 
ports 41 which are connected with a suction chamber or directly with a 
suction generating device (e.g., the intake of a fan) during those stages 
of angular movement of the conveyor 24 when the cigarettes 37 are to be 
held in the respective flutes 38A or 38B. The prime mover PM of the filter 
tipping machine drives the conveyor 24 in a counterclockwise direction, as 
viewed in FIG. 1 or 2. At the same time, the rotary element 42 is also 
driven in the counterclockwise direction, and this element has several 
(e.g., three) convex peripheral surfaces or facets 43 whose peripheral 
speed matches that of the surfaces 39 on the conveyor 24. The surfaces 43 
are separated from each other by recesses 43A. The maximum distance 
between a surface 39 on the conveyor 24 and the nearest surface 43 on the 
rotary element 42 is preferably slightly less than the diameter of a 
cigarette 37; this insures that the cooperating surfaces 39 and 43 define 
gaps having a width which is slightly less than the diameter of a 
cigarette whereby the cigarettes 37 are caused to roll about their own 
axes as soon as their wrappers are simultaneously engaged by a surface 39 
as well as by a surface 43. Once the rotation of a cigarette 37 ends, such 
cigarette rests in and is attracted to the corresponding flute 38B during 
further transport toward the severing conveyor 26. The sidewise movement 
of a cigarette 37 is interrupted during simultaneous engagement with the 
surfaces 39, 43, i.e., a cigarette moves sideways while it is held in the 
corresponding flute 38A or 38B. The length of each surface 43, as 
considered in the circumferential direction of the rotary element 42, 
preferably equals or closely approximates the length of a surface 39, as 
considered in the circumferential direction of the conveyor 24. As shown 
in FIG. 2, once a cigarette 37 is simultaneously engaged by the conveyor 
24 and rotary element 42, the corresponding surfaces 39, 43 engage the 
wrapper of such cigarette at two points (substantially along two lines) 
which are disposed diametrically opposite each other. 
The testing apparatus of FIGS. 2 and 3 comprises two discrete 
photosensitive optoelectrical testing units including a unit 44 which 
serves to detect the presence of protuberances or other projections on 
successive cigarettes 37, and a unit 46 which directs one or more beams of 
radiation substantially radially against the wrappers of successive 
cigarettes 37 while such cigarettes rotate about their respective axes. 
The unit 46 can detect holes, frayed ends, unsatisfactory seams and 
similar defects of the wrappers. 
The testing unit 44 comprises a source 47 of radiation, preferably a 
suitable light source, which directs a beam LB of light in parallelism 
with that cigarette 37 which rotates between two cooperating surfaces 39, 
43. The light beam LB is immediately adjacent to the external surface of 
the wrapper of a satisfactory cigarette 37 and then impinges upon a 
suitable transducer 48 shown in FIG. 3. If the light beam LB between the 
source 44 and the transducer 48 is interrupted while a cigarette 37 
rotates about its axis, such interruption is attributable to a projection 
on the wrapper of the respective cigarette 37, e.g., to the presence of a 
crumb in the seam of the wrapper and/or to the presence of a lip or flag 
which develops as a result of unsatisfactory coating of a uniting band UB 
with adhesive paste and unsatisfactory draping of such uniting band around 
the corresponding filter plug FP and plain cigarettes PC. 
The testing unit 46 comprises a plurality of light conducting glass fibers 
51 each of which has an end portion adjacent to the path portion where 
successive cigarettes 37 rotate about their respective axes. The end faces 
of such end portions of the fibers 51 together form an elongated surface 49 
which faces successive rotating wrappers. The surface 49 is surrounded by a 
holder 52 which is mounted on or in the frame F of the filter tipping 
machine. The holder 52 preferably consists of a suitable synthetic plastic 
material. The number of fibers 51 can greatly exceed the illustrated 
number. The length of the surface 49 equals or approximates the length of 
a filter cigarette 37 (see FIG. 3). The end portions which form the 
surface 49 can be softened by partial melting prior to insertion into the 
holder 52. 
The other end portions of light conducting fibers 51 form three bundles 
which are respectively confined in holders 53, 54 and 56. The end faces of 
the leftmost bundles of FIG. 3 form an elongated surface 57 which can 
receive light from a first light source 61 (e.g., a suitable electric 
lamp). The end faces of the rightmost bundle of FIG. 3 form a surface 59 
which can receive light from a source 62 similar or identical to the 
source 61. The end faces of the median bundle of FIG. 3 form a surface 58 
which can transmit light to a photoelectric transducer 63. 
FIG. 3 shows that the fibers 51 of the median bundle (holder 54) alternate 
with the other fibers 51. The fibers 51 of the left-hand bundle (holder 
53) transmit light to the left-hand half of the wrapper of the filter 
cigarette 37 shown in FIG. 3, and the fibers of the right-hand bundle 
(holder 56) transmit light to the right-hand half of the wrapper of such 
cigarette. It will be noted that the upper end portions of fibers 51 which 
constitute the median bundle (holder 54) are distributed along the full 
length of the surface 49. Therefore, such fibers can direct against the 
transducer 63 light beams which issue from the fibers 51 of the other two 
bundles (holders 53, 56) and are reflected by the corresponding portions 
of the wrappers of a rotating cigarette 37 at the testing station. The 
reflected light is uniformly distributed along the photosensitive surface 
of the transducer 63 because each fiber 51 of the median bundle is located 
(at the surface 49) between two fibers of the right-hand or left-hand 
bundle. 
The testing apparatus further comprises means for synchronizing the 
operation of the testing unit 44, 46 with rotary movement of succcessive 
cigarettes 37, i.e., for initiating the scanning steps which are carried 
out by the units 44, 46 in response to start of successive rotary steps 
initiated by the conveyor 24 and rotary element 42. Such synchronizing 
means comprises a disk 64 with lobes 64A and a proximity detector switch 
66 cooperating with the lobes 64A. The switch 66 is connected with the 
light sources 61, 62 by conductor means 68, and with the light source 47 
by conductor means 67. The disk 64 is driven by the prime mover PM so that 
it rotates with the conveyor 24, and the switch 66 interrupts or opens the 
circuits of the light sources 47, 61, 62 whenever it registers with a slot 
64B between two neighboring lobes 64A of the disk 64. 
The exact manner in which the transducers 48, 63 evaluate the signals and 
generate signals for ejection of defective articles 37 is known; 
therefore, the details of the ejecting means which are connected with the 
outputs of the transducers 48, 63 are not shown in the drawing. The 
ejecting means may comprise a solenoid-operated valve which opens a 
conduit for compressed air whenever it receives a signal denoting the 
detection of a defective cigarette 37, whereby the compressed air expels 
the defective article from the flute of the severing conveyor 26. 
The operation is as follows: 
Each filter cigarette 37 which is transferred into the oncoming flute 38A 
of the conveyor 24 is set in rotary motion as soon as its wrapper is 
engaged by the leading edge 143 of the oncoming surface 43 on the rotary 
element 42. At the same time, the proximity detector switch 66 activates 
the testing units 44, 46 so that the scanning of the wrapper of the 
cigarette 37 between the components 24 and 42 begins as soon as such 
cigarette starts to rotate about its own axis. The length of the surfaces 
39 and 42 is preferably such that each cigarette 37 rotates through 
approximately or exactly 360 degrees; this insures complete scanning of 
the entire wrapper of each and every cigarette 37. As a cigarette 37 
begins to rotate about its own axis, it leaves the respective flute 38A, 
rolls along the respective surface 39 of the conveyor 24, and ultimately 
enters the corresponding flute 38B. This terminates the rotary movement of 
the freshly tested cigarette, i.e., such cigarette resumes its sidewise 
movement with the conveyor 24 and is transferred into the oncoming flute 
of the severing conveyor 26. 
The testing unit 44 scans the rotating wrapper for the presence or absence 
of projections or protuberances, such as the aforediscussed crumbs in the 
seams and/or the flags or lips of improperly convoluted uniting bands UB. 
On detection of a crumb and/or flag, the output of the transducer 48 
transmits a signal which is used to segregate the respective cigarette 37 
from other (satisfactory) cigarettes. 
The testing unit 46 ascertains the presence of holes, frayed ends, open 
seams and/or similar defects, and its transducer 63 then transmits a 
signal which is used for segregation of the corresponding cigarette 37 
from satisfactory cigarettes. For example, when the light beams which 
issue from the upper ends of the left-hand bundle of fibers 51 shown in 
FIG. 3 are reflected (or are improperly reflected) by tabacco which is 
visible through a hole in the wrapper of the left-hand plain cigarette PC 
of FIG. 3, the corresponding fibers 51 of the median bundle fail to supply 
requisite amounts of reflected light to the surface 58 whereby the 
transducer 63 transmits a signal which is indicative of a defective 
cigarette 37. The same holds true when the wrapper of the one or the other 
cigarette PC and/or the wrapper (convoluted uniting band (UB) of the filter 
plug FP contains a dark spot (e.g., a smudge or a particle of tobacco which 
adheres to the exterior of such wrapper). 
It is preferred to regulate the suction in ports 41 of the flute 38A in 
such a way that suction is reduced or terminated (at least at both ends of 
the flute 38A) when a cigarette 37 is about to start to roll about its own 
axis, i.e., when the cigarette is to leave the flute 38A in order to roll 
along a surface 39 (i.e., to interrupt its sidewise movement as a result 
of simultaneous contact with a surface 39 as well as with a surface 43). 
When the testing of a cigarette 37 is completed, such cigarette enters the 
oncoming flute 38B and reassumes its sidewise movement with the conveyor 
24. The flute 38B then transfers such cigarette into the oncoming flute of 
the severing conveyor 26. The ports 41 of the flute 38B are connected to 
the suction generating device not later than when such flute receives a 
freshly tested cigarette 37, and the ports 41 remain connected with the 
suction generating device until the freshly tested cigarette 37 reaches 
the transfer station between the conveyors 24 and 26. The rotary element 
42 cannot interfere with sidewise movement of freshly tested cigarettes 37 
because the depth of recesses 43A in the periphery of the element 42 
suffices to insure that the freshly tested articles can move sideways, 
without any hindrance, as soon as their wrappers are disengaged from the 
respective surfaces 43. 
The proximity detector switch 66 automatically deactivates the testing 
units 44, 46 as soon as a freshly tested cigarette 37 enters the 
respective flute 38B. 
If desired, the surfaces 39 and/or 43 can be grooved, channeled, coated 
with friction generating material and/or otherwise roughened to reduce the 
likelihood of slippage of such surfaces with respect to the wrapper of a 
cigarette 37 therebetween. 
An important advantage of the improved method and apparatus is that the 
articles to be tested need not be moved from their customary path, i.e., 
that the testing takes place in a predetermined portion of the customary 
path along which the rod-shaped articles advance in a filter tipping or 
like machine. It is clear that the testing apparatus can be installed 
downstream of the severing conveyor 26 to scan filter cigarettes of unit 
length. Also, the testing apparatus can be used with equal advantage in a 
cigarette maker, in a machine for the manufacture of filter plugs, in a 
machine for the making of plain or filter tipped cigars or cigarillos 
and/or in any other machine which produces and/or processes rod-shaped 
articles forming part of or constituting smokers' products. 
The possibility of testing successive cigarettes during transport along 
their normal or accustomed path brings about many important and unobvious 
advantages. Thus, successive testing operations can be carried out at the 
rate at which the machine produces and/or processes rod-shaped articles, 
the likelihood of misalignment of articles during transfer from or back 
into their normal paths is eliminated, and the wrappers of the cigarettes 
are less likely to be damaged and/or defaced as a result of total absence 
of the need for transfer from the normal path. 
Another important advantage of the improved method and apparatus is that 
the wrapper of each and every cigarette can be readily tested to ascertain 
the presence or absence of practically all defects, namely, defects which 
can and defects which cannot be ascertained by resorting to pneumatic 
testing apparatus. Adequate testing or scanning of each and every portion 
of each wrapper is insured by rotating the articles through angles of 
approximately or exactly 360 degrees. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic and specific aspects of our contribution to 
the art and, therefore, such adaptations should and are intended to be 
comprehended within the meaning and range of equivalence of the claims.