Process and apparatus for the checking of cigarettes

For the checking of cigarettes for their correct formation in terms of a sufficient tobacco content, electrooptical test processes have been employed for a relatively long time. The use of these processes has hitherto made it necessary to employ high-performance sensitive sensors in order to obtain definite test results. The new process and the corresponding apparatus are intended to make it possible to check cigarettes by the reflection process, especially in a cigarette conveyor (cigarette turret), in which accurate results can be obtained in short test times by means of a simple test device. By means of a special arrangement of the electrooptical sensors for the checking of the cigarettes in test units moved relative to the cigarettes to be checked, it is possible for the cigarettes to be checked for a correct tobacco content, by contactless sensing, either during stationary phases or during rotational movement of the cigarette conveyor (cigarette turret). At the same time, the high reflecting capacity of cigarette paper is utilized for checking the tobacco content.

BACKGROUND OF THE INVENTION 
The invention relates to a process for the checking of cigarettes for the 
correct formation of these at their ends by means of electrooptical 
sensors which possess transmitters and receivers and by means of which a 
test beam (light beam) is directed onto at least one end (end face) of the 
cigarettes and reflected light is measured. The invention relates, 
furthermore, to an apparatus for the checking of cigarettes. 
Cigarettes are tested in conjunction with the packaging of these; for this, 
the cigarettes are checked for a correct sufficient tobacco content by 
electrooptical sensors. 
The testing of cigarettes by electrooptical sensors is basically known. The 
processes adopted hitherto work either on the transmitted-light principle 
or on the reflection principle. The transmitted-light principle requires 
high-performance sensors which also have to be sensitive enough to react 
even to only slight differences in brightness. The reflection process can 
be used for the checking of cigarettes sometimes only at a high outlay. 
Because of the unfavourable reflecting properties of tobacco, test methods 
based on the reflecting properties of the tobacco can also only be 
employed in conjunction with high-performance sensors. 
SUMMARY OF THE INVENTION 
The object on which the invention is based is, therefore, to provide a 
process for the checking of cigarettes by means of electrooptical sensors, 
which works on the reflection principle, but nevertheless gives accurate 
results in the check for a sufficient tobacco content in very short test 
times. 
To achieve this object, the process according to the invention is 
characterized in that the test beam is directed onto the end face of the 
cigarette at an acute angle, especially at an angle of less than 
45.degree., in such a way that, when tobacco is missing in the region of 
this, light is reflected by cigarette paper. 
In the process according to the invention, when there is a deficient 
tobacco content at a cigarette end, the test beam striking an inner face 
of the cigarette paper at an acute angle is reflected back and recorded by 
the receiver arranged concentrically relative to the transmitter. This 
process therefore utilizes the favourable reflecting properties of paper 
in order to check the cigarette ends for a sufficient tobacco content. 
For the checking of one cigarette, there are preferably two sensors which 
are located opposite one another over the circumference and which form a 
sensor pair. For the checking of several cigarettes arranged in a row, the 
sensors, especially the sensor pair, are moved relative to the cigarettes, 
the end faces of the cigarettes being sensed by the test beams. The 
checking of the cigarettes of a cigarette group takes place in several 
part groups, the cigarettes of each part group being checked 
simultaneously. 
The check can be carried out either during the stationary phases of a 
cigarette turret or during the movement of this. A check of the cigarettes 
of a cigarette group during the stationary phases takes place in two 
successive test stations, every second cigarette of all the rows of each 
cigarette group being checked by a test unit. In the check during the 
movement of the cigarette turret, all the cigarettes of a cigarette group, 
divided into several part groups, are checked in succession. 
The apparatus for the checking of cigarettes according to the 
abovementioned process consists essentially of a test unit formed from 
several sensors which, combined to form sensor pairs, are arranged in a 
sensor carrier, specifically in such a way that the individual sensors 
form an angle smaller than 45.degree. relative to the end faces of the 
cigarettes. The sensor pairs are respectively arranged on the sensor 
carrier of the test unit parallel to one another and at a distance from 
one another corresponding to two oblique rows of the cigarette group. 
In an exemplary embodiment of the apparatus, for the checking of cigarette 
groups in an intermittently rotatable cigarette turret there are two test 
units. These are movable past the end faces of the cigarettes in two 
successive test stations during the stationary phases of the cigarette 
turret, in such a way that the sensor pairs are movable to and fro 
parallel to the alignment of the oblique rows. For the checking of the 
cigarettes, the two test units each have four sensor pairs. Every second 
cigarette of all the rows of a cigarette group is checked in each of the 
test stations. The to-and-fro movement of the test units takes place by 
means of a rack mechanism. 
In a further advantageous exemplary embodiment of the apparatus for the 
checking of cigarettes, the check is made during the rotational movement 
of the cigarette turret. For this purpose, a test unit is movable in a 
plane parallel to the end faces of the cigarettes biaxially, specifically 
axially transversely relative to the longitudinal axes of the cigarettes. 
For the checking of all the cigarettes of a cigarette group by means of a 
test unit, the test unit has three sensor pairs. The biaxial movement of 
the test unit in the plane parallel to the end faces of the cigarettes is 
executed by means of a pivoting mechanism. A further feature of the 
invention relates to the design of the pivoting mechanism. 
Two exemplary embodiments of the invention are explained in detail below by 
means of the drawings. In these:

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
The procedure here involves the checking of the end regions of cigarettes. 
During the manufacture of cigarettes, defective cigarettes occur 
relatively frequently for production reasons. These defective cigarettes 
have to be sorted out with the least possible influence on the production 
cycle. This presupposes the installation of devices which are capable of 
identifying defective cigarettes and of generating a corresponding error 
signal leading to the ejection of the defective cigarettes. 
In this particular case, electrooptical sensors 11, 12, in which a 
transmitter part and a receiver part are incorporated, are provided for 
defect identification and for emitting an error signal. FIG. 1 shows, as 
the simplest arrangement, a test unit 13 consisting essentially of a 
sensor carrier 14 which receives a sensor 11, 12 in an oblique socket 15 
in each of its lateral end regions. The cigarette 10 to be checked is 
arranged centrally between the two sensors 11, 12 and is located with its 
end face 16 at such a distance from the sensor carrier 14 that the test 
beams 17, 18 originating from the sensors 11, 12 strike the end face 16 of 
the cigarette 10 at an acute angle 19. In the particular case, the angle 
19 amounts to 20.degree. . Because the test beams 17, 18 enter the end 
region of the cigarette 10 at an acute angle, one or both test beams 17, 
18 strike the inner face of cigarette paper 22 wrapping the tobacco 20, 
depending on the size of a defect 21 occurring when tobacco 20 is missing. 
At least some of a test beam 17, 18 is reflected back and thus reaches the 
receiver of the sensor 11, 12. The sensor 11, 12 then generates a 
corresponding error signal. 
If the cigarette 10 is formed correctly in its end region, that is to say 
if there is a complete tobacco content in the region of the end face 16, 
the test beams 17, 18 are absorbed by the tobacco 20, so that there is no 
error signal. 
The striking of the end face 16 of a cigarette 10 by the test beams 17, 18 
at the acute angle 19 makes it possible to detect even relatively small 
defects 21. Since defects 21 have edge regions which terminate relatively 
flat and which take up a large region of the end face 16, two sensors 11, 
12 combined to form a sensor pair 23 are usually sufficient to identify 
defects 21 in the region of the end face 16 with sufficient reliability. 
The above-described testing of individual cigarettes 10 can take place 
during the standstill or the movement of the cigarettes 10, and the test 
unit 13 can wait in the position of rest or is moved. The only criterion 
is that at a particular moment in a relative movement between a cigarette 
10 and the test unit 13 or the sensor pair 23 the test beams 17, 18 can 
strike the end face 16 of the cigarette 10 to be checked, in the way 
described above. 
The process described and the apparatus also make it possible to check 
cigarettes 10 in cigarette groups 24. The exemplary embodiment illustrated 
in FIG. 4 shows the checking of cigarettes 10 in conjunction with the 
packaging of these. Shown here is a cigarette turret 25 which is 
intermittently rotatable in a vertical plane after a cigarette magazine 26 
of a packaging machine. The cigarette turret 25 is equipped with a 
plurality of pockets 27 over its circumference. 
The cigarettes 10 are extracted from the cigarette magazine 26 by slides in 
a known way and are fed in the longitudinal direction, thereby 
respectively forming a cigarette group 24, to the cigarette turret 25, 
particularly pockets 27 located in the upper region. In the present case, 
the two upper obliquely directed pockets 27 are appropriately each filled 
with a cigarette group 24 simultaneously. The cigarette turret 25 is 
thereafter advanced a division corresponding to a pocket 27. 
The cigarette groups 24 consist of several rows 29, 30, 31 extending along 
a pocket wall 28. Within these rows 29 to 31, the cigarettes 10 are in a 
close-packed position. In the present exemplary embodiment, the cigarettes 
10 of adjacent rows 29 to 31 are arranged offset relative to one another 
(saddle position), so that the cigarettes 10 are arranged in line with one 
another both in the rows 29 to 31 and in oblique rows 32, 33, 34, 35, 36 
and 37. 
As a result of the rotation of the cigarette turret 25, the cigarette 
groups 24 so formed pass initially into a first test station 38 and 
thereafter into a second test station 39. Each test station 38, 39 is 
equipped with a test unit 40, 41. When, as with filterless cigarettes 10, 
both free ends of the cigarettes 10 have to be checked, further test units 
(not shown here) are arranged on the opposite side of the cigarette turret 
25. 
The test units 40, 41 are equipped with four sensor pairs 42, 43, 44 and 45 
and are moved passed the end faces 16 of the cigarettes 10 in the 
direction of double arrows 46, 47. 
The method by which the cigarettes 10 of the cigarette group 24 are checked 
in two successive test stations 38, 39 can be taken from FIG. 4. During 
the checking of the cigarettes 10, the test units 40, 41 execute a stroke 
movement indicated by the double arrows 46, 47, specifically in such a way 
that, in each stationary phase of the cigarette turret 25, a movement in 
the opposite direction relative to the preceding stationary phase is 
executed. FIG. 4 shows the position of the test units 40, 41 at the start 
of a check of the cigarettes 10. In each test station 38, 39, the 
cigarettes 10 are tested in three part groups 48, 49 and 50, the 
cigarettes 10 of each part group being checked simultaneously by means of 
a sensor pair 42 to 45. In this way, initially every second cigarette of 
the row 29 and an individual cigarette 51, which together form the part 
group 48, are checked simultaneously by the sensor pairs 42, 43, 44 and 45 
in the test station 38. As a result of the continuous movement of the test 
unit 40 in the direction of the cigarette turret 25, next every second 
cigarette 10 of the row 30, particularly the part group 49, is checked by 
the sensor pairs 42, 43 and 44. The last part group 50 in the test station 
38 is formed from every second cigarette 10 of the row 31, with the 
exception of the individual cigarette 51. The cigarettes 10 of this part 
group 50 are checked by the sensor pairs 42, 43 and 44. The cigarettes 10 
in the test station 39 are checked in a similar way. Here, the cigarettes 
10 of the respective part groups 52, 53 and 54 are checked in succession, 
the first part group 52 being composed of every second cigarette 10 of the 
row 29, including an individual cigarette 55. All the sensor pairs 42, 43, 
44 and 45 of the test unit 41 are required for the checking of the part 
group 52. The part groups 53 and 54 are checked by means of the sensor 
pairs 43, 44 and 45. 
Because the cigarettes 10 of the rows 29, 30 and 31 are arranged in a 
saddle position, the cigarettes 10 of every second oblique row 32, 34 and 
36 and the individual cigarette 51 are checked in the test station 38 and 
the cigarettes 10 of every second oblique row 33, 35 and 37 and the 
individual cigarette 55 are checked in the test station 39. 
For the checking of the cigarettes 10 arranged in the oblique rows 32 to 37 
and of the individual cigarettes 51 and 55, the sensor pairs 42 to 45 of 
the test units 40, 41 are arranged at a distance from one another 
corresponding to two oblique rows 32 to 37 and offset respectively 
relative to one another. This ensures that, at a particular moment in the 
movement of the test units 40, 41 past the end faces 16 of the cigarettes 
10, the respective end faces 16 of the cigarettes belonging to a part 
group 48 to 50 or 52 to 54 are checked simultaneously. 
The to-and-fro movement of the test units 40, 41 is executed by means of a 
rack mechanism 56 which is driven by the drive unit (not shown) of the 
cigarette turret 25 in synchronism with the timing sequence of the latter. 
In particular, the drive is obtained by means of a pinion 58 which is 
located on a drive shaft 57 and which acts on a rack 59 connected firmly 
to the test unit 40, 41. For guiding the rack 59, a sliding guide 61 is 
provided in a housing jib 60 which also receives the entire rack mechanism 
56. 
A further exemplary embodiment of the apparatus is shown in FIG. 7. In 
contrast to the abovementioned exemplary embodiment, here the checking of 
the cigarettes 10 in the cigarette turret 25 takes place during the 
movement of the latter. Thus, a test unit 65 equipped with three sensor 
pairs 62, 63 and 64 is moved axially transversely relative to the 
longitudinal axes of the cigarettes 10 by means of a pivoting mechanism 
66. 
FIGS. 8 and 7 illustrate, in the order mentioned, two successive states of 
the relative movement between the test unit 65 and a cigarette group 24. 
FIG. 8 shows the test unit 65 with the sensor pairs 62, 63 and 64 which 
are arranged parallel to, and at a distance of two oblique rows 32 to 37, 
from one another and which are arranged without any lateral offset 
relative to one another. The cigarettes, each checked simultaneously by a 
sensor pair 62 to 64, are arranged in a part group 67. This part group 67 
is formed from a cigarette 10 of each of the rows 29, 30 and 31, the end 
faces 16 of the cigarette 10 being arranged in a straight line, 
specifically at a distance from one another corresponding to two oblique 
rows 32 to 37. FIG. 7 shows the test unit 65 during the checking of a part 
group 68 following next during the rotational movement of the cigarette 
turret 25. During the checking of the cigarettes 10 of the cigarette group 
24, a row 29, 30, 31 is assigned to each sensor pair 62, 63, 64 in the 
order mentioned. 
The checking of the cigarettes 10 during the rotational movement of the 
cigarette turret 25 requires a biaxial pivoting of the test unit 65. For 
this purpose, the pivoting mechanism 66 is formed essentially from a 
supporting lever 69 and a pivoting lever 70 which are each articulated at 
one end in a common pivot bearing 71 on a machine stand 72 of the 
packaging machine. 
The test unit 65 consists of a sensor carrier 73 receiving the sensor pairs 
62 to 64, with a pivoting extension 74 projecting laterally from this. In 
a transitional region 75 to the pivoting extension 74 and at the free end 
of the pivoting extension 74, the test unit 65 is connected in an 
articulated manner to the other end of the supporting lever 69 and of the 
pivoting lever 70. At the same time, the connection between the test unit 
65 and the supporting lever 69 is made via a rotary joint 76 and the 
coupling between the pivoting extension 74 of the test unit 65 and the 
pivoting lever 70 is made via a combined rotary sliding joint 77. 
This design of the pivoting mechanism 66 makes it possible for the test 
unit 65 to execute a pivoting movement about the pivot bearing 71 via the 
supporting lever 69. Superposed on this pivoting movement is a deflection 
of the pivoting lever 70 likewise mounted in the pivot bearing 71 and 
connected to the pivoting extension 74 of the test unit 65 via the rotary 
sliding joint 77, causing a pivoting movement of the test unit 65 in the 
rotary joint 76. The deflections of the supporting lever 69 and of the 
pivoting lever 70 about the pivot bearing 71 are indicated by double 
arrows 78 and 79 respectively. 
Of course, the checking of cigarettes 10 by the process explained in detail 
here is not tied to a specific formation of the cigarette groups 24 in the 
cigarette turret 25. By appropriate changes of the distances between the 
sensor pairs 42 to 45 or 62 to 64 and/or a change of the number of sensor 
pairs 42 to 45 and 62 to 64 on a test unit 40, 41 and 65, cigarettes 10 
can be checked in any possible formation of the cigarette groups 24.