FR2470077A1 - METHOD AND DEVICE FOR ADJUSTING BAND ROLLER CYLINDERS - Google Patents

Abstract

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

Description

Method and device for adjusting rollers

bands.

  The present invention relates to a method for adjusting the winding or unwinding of web material from a roll and a device for carrying out this method. In modern coating and processing facilities, the web material is wound on or rolled out of cylinders with a very high speed, the most

  O10 often going up to 300 meters per minute.

  To prevent the rear edges of the strip that is unrolled are torn at this speed of the cylinder on which the strip is wound, and thus possibly damage both the strip and the adjacent parts of the machine, it is generally taken precautions to reduce or Slowly decelerating the unwinding speed of the web when a predetermined number of turns of the web material remains on the roll. Adjustment is frequently done so that mechanical feelers are provided which continually measure the amount of web material remaining on the cylinder and which can slow down the unwinding mechanism when a

  predetermined amount of band remains on the cylinder. Toute-

  mechanical feelers tend to make marks on the belt during unwinding or even to damage it and cause frequent mechanical incidents because of the

  high speed at which the cylinder rotates during the

  cessation of the course of the band. Various procedures have been

  optical dies to measure the number of revolutions of the

  on the cylinder during the unwinding of the strip, but these measures were generally insufficiently

  and have led to this, that the process of

  prematurely, that the back edges of the web are torn at high speed before a

  unwinding speed is possible. Also, this is

  lable for the winding of a strip on a cylinder, but it is in this case mainly for this reason that too little band

is wound on the cylinder.

  The problem of the present invention lies in the fact that the adjustment of the unfolding or winding of my web tape is to be improved with means that are as simple as possible and operating surely, so that

  that an optimal precision is obtained.

  The present invention, which is based on a method of the prior art for adjusting the winding of a strip material on a cylinder or for adjusting the unwinding of a strip material on a cylinder by determining the number of turns on the cylinder, and by changing the rotational speed

  of the cylinder when this number of revolutions reaches a pre-

  completed, the number of revolutions on the cylinder being determined

  using an optical system that controls the thickness

  of the tape on the cylinder, and the problem posed

  is solved by the method which is characterized by using an optical system which comprises a focused light source, an optical assembly and a calibrated linear photodiode device, that this system is placed in such a way that the profile of the periphery of the strip material on the cylinder is formed clearly on the calibrated photodiode device, and the rotational speed of the cylinder is changed when predetermined photodiodes in the device either start receiving light or send signals, or no longer receive light or

no longer send signals.

  In connection with the present invention, the term

  "light" of course includes infrared radiation.

  By the expression "a calibrated linear device of photo-

  diodes ", it is necessary to include photodiodes which are spaced apart

  arranged in series. The relative distance of the photodiodes

  sins is so calibrated that it is equivalent to a given number of turns of the web material on the roll, this depending on the thickness of this web material, and the enlargement (or reduction ) optics of the optical assembly used. Thus, using a strip material of different thickness, it is necessary to make a new calibration of the linear device of photodiodes. Since linear photodiode devices are very expensive and it is not necessary to know exactly the number of turns on the cylinder that when this number is about the last, we can install the linear devices of photodiodes with respect to the cylinder of so that they are when winding the web at the highest point of a fully wound roll, or when unwinding the roll at the highest point of the roll. Preferably, the light source is placed on one side of the cylinder and the linear device is calibrated with 10 photodiodes on the other side, but the two can also

  be on the same side of the cylinder.

  The profile of the periphery of the web material

  must be clearly formed on the calibrated device of photo-

  diodes because a blurred shaded image is not enough

accurate.

  The process of the present invention is particularly

  used for adjusting the unwinding of the web material. A preferred variant being characterized in that the focused light source is placed on one side of the roll and the optical assembly and the calibrated linear photodiode device are placed on the other side of the roll, the source of light and the optical assembly and the photodiode device being arranged such that the profile of the periphery of the strip material on the cylinder is clearly formed on the calibrated device of photodiodes, and that during the continuous course of the ribbon , a continuously increasing number of photodiodes receive light from the light source, and that the rotation speed of the cylinder is decreased or the cylinder is stopped, when a predetermined number of photodiodes receive the light or send the signals, which number corresponds to the number of

  predetermined turns of the web material on the cylinder.

  A particularly advantageous embodiment of the process of the present invention is characterized by the fact that

  a second optical assembly and a second linear device

  area of photodiodes are provided and are placed so that

  the light from the light source is always received

  the number of photodiodes receiving light in the two devices is compared with each other and that the number of revolutions of the strip remaining on the cylinder is compared with the linear device of photodiodes

  calculated from both readings.

  The second optical assembly provided according to the

  cation 3 just described and the second series of photo-

  diodes are used to eliminate erroneous readings caused by the mechanical movement of the

  cylinder on its bearings. This variant is also preferred

  When the strip is to be wound on a cylinder in the form of a tube or hollow core that can be removed. Thus,

  mistakes which would otherwise be due to eccentricity or

  circular shape in this tube or core or

  an outer diameter of the tube or core deviating considerably

  of the prescribed value, or at a position of the axis of that tube or core departing from the initial position,

are continually eliminated.

  As an indication of the existing dimensions in this case, it may be mentioned that a typical roll completely

  wound from a web material made of a material

  plastic film holder, as used

  production in the photographic industry can

  a diameter of 1000 mm. The thickness of the web material may be 0.125 mm and the roll may thus contain 3200 turns on a cylinder 200 mm in diameter. The total length of the strip material is then of the order of 6000 meters, and the course at a speed of 120 meters / minute

  lasts in this case 50.2 minutes. The last 50 laps of the

  In strip form have a total thickness of 6.25 mm and represent 32.4 meters of strip material on the cylinder of 200 mm. The time required to run the last laps at 120 m / minute is only 16.2 seconds. So to be able to unroll most of the roll of the material

  in band at the preferred speed, you have to know very

  the moment for example where there are only 50 laps

  on the cylinder in order to decrease its rotational speed.

  tion. The optical system to be used during the process according to the present invention also makes it possible to detect a

  only round the strip material on the cylinder.

  The control system may give a start signal to a predetermined system for progressive deceleration or the diode system may in the preferred embodiment of the present invention be provided with an electrical output which directly adjusts the speed. of the machine in proportion to the amount of material in

band remaining on the cylinder.

  As mentioned above, the method according to the present invention can be used also during the rolling of the material on the roll to avoid having a large excess of rolled web material. In this case, the optical system is preferably placed on the empty cylinder at a level such as a roll completely wound with material

  band will pocket the path of light from the light source

  to reach certain photodiodes in the linear positive. With the constitution of the strip on the cylinder during the winding of the strip, a stage 20 is reached in which some of the photodiodes can no longer receive light. When the number of photodiodes can no longer receive light approaches the equivalent of the number of revolutions required, the band, the speed of the winding of the strip on the cylinder is controlled and it is stopped when the number of necessary turns is present on

  the cylinder. In this case, the height of the photo-

  diodes above the empty cylinder corresponds to the number of

  predetermined turns of the web material on the cylinder.

  Practically with an embodiment of the present invention, only an approximate control device is possible, which is based on the speed of the band to be adjusted when the roll reaches a certain diameter, but this diameter of the band corresponds substantially to the number of turns predetermined

of the band on the cylinder.

  The object of the present invention is still a

  positive device comprising a cylinder with an adjustable rotation control mechanism and a conventional control system for the number of revolutions of the web material present on each cylinder, which is characterized in that the control system comprises a source a focused light unit, an optical assembly for image formation and a calibrated linear device of photodiodes, that the focused light source is placed on a side of the cylinder and the optical assembly and the photodiode device are

  placed on the other side of the cylinder, the optical assembly

  on the photodiode device the profile of the strip material on the cylinder, so that the light of the light source, orand the cylinder is empty, passes therethrough to reach the photodiode device, but is obscured by the strip on the cylinder when it is completely wound on the cylinder, and that the mechanism

  rotation control is controlled according to the

  g: to the sent by the device of photodiodes.

  Preferably, a second set of

  an optical device and a second linear device of photodiodes, which are arranged in such a way that the light of the light source continuously arrives passing over the

empty cylinder, the optical assembly.

  As light sources, for example, a tungsten filament lamp, a helium laser, are suitable.

  neon or a solid body laser that are used simultaneously

  with a collimator and / or other lenses for

  a substantially parallel light beam.

  In a large number of cases for example, when using the method of the present invention in a

  installation of application or finishing of photo material

  graphic, we prefer to use infrared radiation

come light.

  The present invention is illustrated by the accompanying drawings in which:

  FIG. 1 is a plan view of the device used

  in the present invention; Figures 2 to 4 are views of that of the device shown in Figure 1 showing the successive stages of the

  unwinding of the web material from a cylinder.

  In Figure 1, a roll of strip material 1

  is supported on a cylinder 2 resting on two bearings 3.

  A control means 4 drives the cylinder 2 and causes the unwinding of the strip 5 from the cylinder 2. The control means 4 also includes the adjustment means 6 of

speed.

  On one side of the roll of web material 1 is a light source 8 and a lens 9 for focusing the light. As shown, the focused light

  passing over the empty cylinder 2 and passing through an op-

  10, reaches a linear device of photodiodes 11.

  In addition, we can also see how focused light

  passing on the roll of material in tape and crossing

  another optical unit 12 arrives at another device

linear tif of photodiodes 13.

  Figures 2 to 4 are side views along

of the line A-A in FIG.

  In FIG. 2, the diameter of the roll of material

  in band 1 is so large that no light from the light source

  8 can not reach the photodiode device 13.

  In FIG. 3, more strip materials have been unwound from roll 1 and the light from the light source

  8 can then reach the device 13 by passing on the cylinder

  2 and passing through the optical system 12.

  In Figure 3, the diameter of the web roll is 212.5 mm and the thickness of one turn of web material is 0.125 mm. Thus, 50 rounds of material in band are found

  2. Since the number of laps of

  in which an influence is exerted on the com-

  the speed of rotation of the cylinder 2, by

  6, is pre-set to 50, the control means 4

  In this case, the speed of rotation of the cylinder 2 will gradually slow down until the stage shown in FIG. 4 is reached, where there is no longer a revolution of strip material on the cylinder 2, which then continues to turn

  very slowly before stopping or stopping.

  In FIGS. 1 to 4, the two photo

  diodes 11 and 13 have 256 photodiodes in series and the

  the linear device reaches 6.4 mm. The visible height of the profile of the web roll, represented by the mark 14,

  is 2.6.4 mm = 12.8 amm. This is the profile formed on the

by

  photodiodes tif / optical assembly. This optimal reduction

  only optical assemblies O10 and 12 allow the use of smaller linear devices and shorter optical systems. The last 50 laps of tape on the cylinder are

  determined by comparing the signals received from the

  photodiodes 11 and 13. This calculation is performed in an electronic processor (not shown) which receives the

  10 output signals of the two devices 11 and 13.

  In practice one can use two commercial cameras that combine optical assemblies O10 and 12 with the linear devices of photodiodes ll and 13. A camera of this kind is the "Linescan" camera sold by Integrated Photomatrix Ltd., Dorset, England . A camera of this kind contains a device of 256 photodiodes each spaced 0.025 mm. Each camera has a focal length of 250mm, which gives an optical reduction of 2: 1 for a

  working distance of 750 mm. The field of view of each camera

  ra is 12.8 mm and the separating power of each diode is

  0.05 mm. The total length of the camera is 460 mm.

  As a light source it is possible to use a normal tungsten filament lamp having a condenser in order to

  produce the collimation of the light beam.

Claims (6)

  1. Method for adjusting the winding of a   material on a cylinder or to adjust the   a number of turns on the cylinder, and by changing the speed of rotation of the cylinder when this number of revolutions reaches a predetermined value, the number of revolutions on the cylinder being   determined using an optical system that controls the   radial thickness of the strip on the cylinder, the method   being characterized by the fact that an optical system is used which comprises a focused light source (8, 9), an optical assembly (12) and a calibrated linear photodiode device (13), that this system is placed so that such that the profile of the periphery of the web material on the cylinder is formed clearly on the calibrated device of photodiodes, and that the rotational speed of the cylinder is   modified when predetermined photodiodes in the   or send signals, or no longer receive light or send more signals.   2. Method according to claim 1, with a view to   adjust the unwinding of a roll of material in a strip   ending in the course of unwinding the number of turns of the strip material remained on the cylinder and modifying the   speed of rotation of the cylinder when the number of revolutions   to a predetermined value, characterized in that the focused light source (8, 9) is placed on one of the sides of the roller (1, 2) and the optical assembly (12) and the calibrated linear device photodiodes (13) are placed on the other side of the roller, the light source as well as the optical assembly and the photodiode device being   arranged in such a way that the profile of the circumference of the   strip on the cylinder is clearly formed on the calibrated device of photodiodes (13), and that   during the continuous progress of the band, a growing number   continuously, photodiodes receive the light from the light source and the rotation speed of the cylinder is decreased or the cylinder is stopped, when a predetermined number of photodiodes receive the light or send signals, which number corresponds to the number of revolutions   predetermined of the strip material on the cylinder.   3. Method according to claim 2, characterized in thata second optical assembly (10) and a second linear device of photodiodes (11) are provided and are placed so that the light of the light source (8) is always received, passing on the part of the cylinder (2) without tape, on the linear device of photodiodes, that the number of photodiodes receiving the light in the two devices (8, 9, 12, 13 or 8, 9, 10, 11) are compared with one another and that the number of revolutions of the strip (1) remaining on the cylinder (2)   be caleulé from the two readings.   4. Device for carrying out the process   according to claim 1, comprising a cylinder with a mechanism   rotation control mechanism (4, 6) and a conventional control system for the number of revolutions of the web material present on each cylinder, characterized in that the control system comprises a light source (8, 9), an optical assembly (10) for imaging and a calibrated linear device of photodiodes (11), that the source of u = ir (8,9) is placed on one side of the cylinder and the optical assembly and the photodiode device are placed on the other side of the cylinder, the optical assembly   forming on the photodiode device the profile of the material   in a strip on the cylinder, so that the light of the light source, when the cylinder is empty passes therethrough to reach the photodiode device, but is obscured by the strip on the cylinder when it is completely wound on the cylinder, and that the rotation control mechanism is controlled according to the signals   sent by the photodiode device.   5. Device according to claim 4, characterized by a second optical assembly (12) and a linear device of photodiodes (13) which are arranged in such a way that the   light from the source of gender (8) reaches the second set   optical fiber passing continuously over an empty portion of the cylinder and by means means that controls the rotation mechanism 11 (4, 6) as a function of signals from both devices linear photodiodes (11, 13).   6. Device according to any one of the claims   4 and 5, characterized in that the collimated light source is a tungsten filament lamp, a helium laser,   neon, a solid-body laser, or a radiation source   frarouge which are used together with a collimator and /   or other lenses to provide a sensitive light beam parallel.