FR2523724A1 - DEVICE FOR THE CONTINUOUS CONTROL OF THE CONTENT OF A TUBULAR ENVELOPE - Google Patents

Abstract

THE DEVICE INCLUDES A HEAD 16 PRESENTING A PASSAGE 24 FOR THE TUBULAR ENVELOPE TO BE CONTROLLED 1 WHICH MOVES LONGITUDINALLY CONTINUOUSLY. THIS PASSAGE 24 PRESENTS, ON ONE SIDE, A LIGHT EMITTING SOURCE 41 AND ON THE OTHER SIDE A PHOTOELECTRIC SENSOR ELEMENT 42. PASSAGE 24 PRESENTS A U-SHAPED SECTION WITH THE PARALLEL WALLS AND THE BOTTOM OF WHICH HAS A SHAPED SURFACE FROM DIEDRE SAILLANT 25, WHOSE AREA IS LOCATED AT LEAST APPROXIMATELY IN THE BISECTOR PLANE OF U, AT A DISTANCE FROM THE TRAJECTORY OF THE LIGHT RAY EQUAL TO AT LEAST ONCE AND HALF THE WIDTH OF PASSAGE 24. HEAD 16 CAN BE RAISED. BY PIVOTING. THE DEVICE IS PARTICULARLY INTENDED FOR CHECKING THE MANUFACTURING OF CIGARETTE FILTERS.

Description

The present invention relates to a device for the control in

  Continuous content of a tubular envelope

  moving longitudinally in a continuous manner, in parti-

  to control a cigar filter rod.

  rette, during its manufacture, and the control of the cut of this rod rods, as well as for the control of the filling of the cigarettes themselves This device comprises a head having a passage for the envelope to

  control and carrying a light emitting source emitting

  radiation transverse to the passage, in direct

  a photoelectric sensor element located behind

  a transverse slot, on the other side of the passage and

  assigned to a signal processing circuit picked up.

  Continuous optical control of the density of a

  a continuously manufactured cigarette filter

  laid in patent CH-576 242 The rod passes through a control head having an annular passage leaving a game as low as possible On each side of the passage end beams of optical fibers, the transmitter

  light and the other sensor This design has been

  socket, with a photoelectric sensor, in patent CH-621 245 and in patent CH-627 119 for the control of the cutting device of a composite filter requiring a cut in a specific place The passage through the head

  of control, for the rod to be checked, is always

  The annular shape was necessary for guiding reasons, since it was logically sought to limit to a minimum the freshness of the rod, the transverse displacements of the

  wand which has the effect of modifying the optical signal

  Therefore, the radial clearance was also limited to one half

  nimum In order to reduce the reflection of the light by the inner wall of the annular passage, it has been coated

  anti-reflective optical varnish.

  However, there is a parasitic light which, in the recording of the measured optical signal, results in an instability of it. This is a non-reflective synthetic material to form the body of the ring.

  due to the fact that there is still some

  bending on the cylindrical wall of the passage, especially towards the points of tangency of the planes parallel to the path of the light ray. Furthermore, the friction of the rod on the wall of the passage leads to the formation of more or less white dust, dust paper, or even white filter material, which is an indirect source of parasitic light, this all the more

  it is necessary to leave sufficient radial clearance,

  taking into account the variation in the diameter of the

  bonded by two strips of paper.

  The main purpose of the invention is to eliminate the

  stray light due in particular to reflections.

  For this purpose, the device according to the invention is

  characterized by the fact that said passage has a section

  U-shaped with parallel walls, preferably vertically

  wedges and whose bottom has a surface in the form of a protruding dihedral, with flat or concave faces, whose ridge

  is located at least approximately in the plane bisecting

  the A, at a distance from the path of the light ray

  equal to at least one and a half times the width of the passage.

  The U-shaped passage is preferably arranged vertically, its opening at the bottom, in the direction of the strongest movements of the rod due to the guidance system of the guns of the cutting device which immediately follows the

  optical control device Therefore, contrary-

  to what has always been sought after,

  to control can move freely vertically in the

  passage in the form of U Gold, despite this frolic, the signal op-

  The measured tick is proving very stable and no

  more parasitic signal. Thanks to the form of

  the section of the passage, the reflections on the walls of the pas-

  wise no longer influence the sensor On the other hand, the

  -3- Sessions tend to be evacuated automatically It is

  in addition easier to clean the passage.

  But another significant benefit is corollary.

  both, namely the possibility of disengaging the control head from the stick by raising it or away from it,

  which makes it easier to get started, since it is no longer

  to introduce the end of the rod into the annular passage of the head, and facilitate any control or service of the machine without the need to cut

the wand in formation.

  The appended drawing represents, by way of example, a

embodiment of the invention.

  Figure 1 represents, schematically, the ter-

  of a machine for the manufacture of cigar filters

  equipped with a control and control device

the cup.

  Figure 2 shows a side view, to a larger view

  scale of the optical control device.

  FIG. 3 represents a front view of this device.

tif optical control.

  Figure 4 is a top view of the same device.

  FIG. 5 is a diagram illustrating the insensitivity of the optical control device to the vertical displacement of

  the wand to control, compared to a device se-

in the prior art.

  The installation shown diagrammatically in FIG. 1 is described in patent CH-621 245.

  continuous manufacture of cigarette filters, in particular

  Composite filters and cavity filters filled with a filter granulate Filters formed continuously by the

  end-to-end juxtaposition of cell acetate cylinders

  and cavities automatically filled with granules and wrapped two strips of paper arrive in the form of a rod 1 driven by an endless belt 2 to

  through the optical control device 3 in front of a dis-

  -4- positive cutting 4 which cuts the rod 2 rods, which are deflected laterally of their trajectory by a distribution wheel 6 with helical grooves which allows the rods to engage in the grooves 7 of a receiving drum which distributes them on a trans-

  carrier moving perpendicular to the plane of the drawing.

  Defective rods are removed pneumatically by

  a nozzle 8 controlled by an electromagnetic valve 9.

  Defective sticks are driven into a hopper of

  The optical signal delivered by the

  Control 3 allows for quantitative control of the

  pleating of the filter cavities, to control the location and length of the filter segments and to control the

  cutting device 4 according to the position of the elements

  For this purpose, a signal processing circuit is provided, for example a circuit as described in patent CH-627 119. The coil 1 is introduced.

  by hand in a pre-guide gun 11 preceding the

  perie 4 provided with two guiding cannons 12 and 13 between

  which works the knife 14 of the cutery.

  The detection device 3 will be described in relation with FIGS. 2, 3 and 4 The device is mounted on a vertical plate 15 fixed on the frame 40 of the machine The actual measuring head 16 is pivotally mounted on this plate around a horizontal axis 17 secured to a manneton 18 at the end of which is articulated, about an axis 19, the piston rod 20 of a pneumatic cylinder 21 to single effect whose cylinder is articulated on the plate

around an axis 22.

  The head 16 is composed of two asymmetrical parts 16a and 16b made of solid metal joined to each other along a vertical joint plane 23 The part 16a is cut so as to form a prismatic passage 24 in the head,

  having a generally U-shaped cross-section

  poured, whose bottom 25 is in the form of a salient dihedral of which -5 _

  the ridge is located in the bisecting plane of the passage 24.

  Part 16b has a recess 26 in which is mounted an infrared emitting diode 27 mounted on a

  flange 41 and powered by a pulsed light source.

  In front of this emitting diode 27, whose hemispherical emitting surface has a diameter of less than 2 mm, is mounted a window 28 constituted by a sapphire wafer 0.6 mm thick, placed a few tenths of a millimeter thick.

  millimeters of the diode 27 and embedded in a metal cover

  The portion 16 of the head also has a recess 30 in which is housed a receiving cell.

  31, for example a mounted Si-PIN photodiode, with a

  of the signal processing circuit, on a flange 42.

  This photodiode is practically in contact with a 0.05 mm thick metal cover, coated on the flange side of an absorbent optical layer and glued on a sapphire wafer 32 identical to the wafer 28 glued and embedded in a hollow. a metal cover 33 closing the recess 30 and provided with a central cut-out for the receiving diode 31, as also the cover 29 The cover lying in front of the receiving diode 31 has a slot

  vertical width of about 0.8 to 1 mm and a

  equal to 0.4 to 0.6 times the width of passage 24, that is,

  that is to say the diameter of the flange 1 which passes through the slot with as little lateral clearance as possible, for example of the order of 0.7 mm on each side. The dimensions of the slot are, for example, 1 mm by 4.5 mm The edge of the dihedron 25

  is located at a distance from the trajectory 34 of the light ray

  light emitted by the emitting diode 27 equal to one and a half times the width of the passage 24 that is to say a little more than one and a half times the diameter of the coil 1 This distance

  could of course be superior, but it proved

  It is perfectly sufficient to eliminate the effects of stray light due to reflection. The walls of the passage 24, including the dihedron 25, are also treated to obtain diffusing absorbing surfaces.

  eg sandblasted, then matte black alumite or coated

  green optical black dye The vertical slot of the cache of the receiving diode 31 is of course located on

  the trajectory 34 of the light beam emitted by the diode emits

  The transmitter diode and the circuit associated with the receiving diode are connected to unrepresented flexible conductors. The same is true of the supply tube of the pneumatic cylinder.

  As shown in FIG. 2, the head can be taken

  in a position 16 'shown in phantom, by pivoting about its axis 17, in the direction of the arrow F, to occupy the position 16' shown in phantom

  mixed, under the effect of the thrust of the pneumatic cylinder 21.

  When the pressure in the jack 21 is released, the return spring thereof brings the head back to the position of

  work shown in full lines.

  raised the head 16, the flange 1 is completely clear of the head which allows easy start and

  prevents accidental damage to the head.

  control and cleaning sapphire chips, including glue deposits left by the contact of the coil 1, are also facilitated The vertical position of the

  passage 24 is favorable because it facilitates evacuation

  tomatic, by gravity, dust formed by abrasion of the casing of the flange 1 With regard to the result

  optics and the possibility of clearing the head, the slot

  However, it should be equally oblique or even horizontal.

  Figure 5 illustrates, in the form of a diagram of

  surprising result obtained by the shape of the pas-

  wise 24 The vertical deviation d,

  in millimeters, of the strand 1, from a position of

  pos 0, and on the ordinate the ratio V / Vo between the signal me-

  at rest (1) and the signal measured in different po-

  The curve a is the measuring curve obtained with a measuring head according to the prior art, that is to say a cylindrical ring-pass head with minimum clearance. The curve b is the curve. Measuring device obtained with a measuring head according to the invention It should be considered that in the head according to the prior art, the vertical loop of the coil is very limited by the wall of the annular passage, whereas in the head according to

  the invention, this vertical frost is absolutely not limited.

  It can be seen that with the head according to the prior art, the report

  port V / Vo is in the order of 1.3 to more than 1.5 for a gap of 1 mm, whereas this V / Vo ratio is only 0.97 at

0.99 'for a gap of + 1 mm.

-8-

Claims (5)

CLAIMS -   1 Device for the continuous control of the contents of a tubular casing moving longitudinally   in a continuous manner, comprising a head having a step   wise for the envelope to be controlled and carrying a source   emitting light emitting radiation transverse-   on the way to a photo sensor element   located behind a transverse slot,   the other side of the passage and associated with a processing circuit   detected signal, characterized in that said   passageway has a U-shaped section to the walls   and whose bottom has a surface in the form of   protruding dihedron, the ridge of which is at least approximately   in the bisecting plane of the U, at a distance from the trajectory of the light ray equal to at least times and a half the width of the passage.   2 Device according to claim 1, characterized in that the walls of the U-shaped passage are   vertical and that the passage is open downwards.   3 Device according to any one of the claims   1 or 2, characterized in that the length of the transverse slot in front of the sensor element is included   between 0.4 and 0.6 times the width of the passage.   4 Device according to any one of the claims   1.2 or 3, characterized in that the light source   and the sensor element are placed respectively   a sapphire plate flush with the surface of the pas-   wise. Device according to any one of claims 1, 2, 3 or 4, characterized in that the head is movable in a plane parallel to the bisecting plane of the U, so that it can be disengaged from the tubular casing to be controlled .