Needling machine for needling a web or a web of fibres, in particular a nonwoven

Abstract

The needle-tapping installation comprises a needle board having a field of needles and means for driving the needles in a back-and-forth motion, in particular in the vertical direction, such that the needles, in one direction of motion, penetrate a web or sheet of fibers, in particular non-woven, to pass through it in a transverse direction, in particular perpendicular, to the direction in which the web or sheet of fibers moves in front of the needles, and then in a second direction of motion, emerge from the sheet or web of fibers, with fiber dust accumulating on the board between the needles, and means are provided for monitoring the quantity of fiber dust accumulated on the board between the needles.

Description

[0001] The present invention relates to a needling machine installation comprising a needle board whose needles perform a back and forth movement inside a sheet or web of fibers, in particular non-woven, passing in front of them, with a view to consolidating it. The present invention also relates to a method of operating an installation of this type.

[0002] In needling machines, it is desirable to be able to continually increase the production rate, and in particular to avoid untimely interruptions to the needling line.

[0003] From EP 1811072 A1, a needling machine is known comprising a needle board passing back and forth through a web of fibers which move perpendicular to the needles between a perforated plate forming a support table and a perforated plate forming a stripper, the perforations being crossed by the needles. Fiber dust accumulates on one and / or the other of the two plates respectively forming a support table and a stripper which causes vibrations of the needling machine and means are provided to control in real time the operation of the needling machine.

[0004] From EP 1384804 B1, a needling machine is known comprising a needle board and two plates between which a sheet of fibers to be needled passes and means for eliminating flying fibers by intermittent air jets on the outer faces of the plates.

[0005] The present invention aims to overcome the drawbacks of the prior art by providing a needling machine installation which makes it possible to increase the production rate of consolidated sheet or veil, in particular by avoiding untimely interruptions of the line.

[0006] According to the invention, an installation is according to claim 12.

[0007] The inventors of the present invention have realized that long-term blockages of the line are often due to fiber dust accumulating between the needles on the face of the board from which they protrude, this dust, by accumulating, forming clumps which can cause the breakage of one or more components of the installation, which leads to the shutdown of the installation for long periods, for example when the needles pass through a stripper plate, strike the stripper plate and subject it to excessive vibrations and / or deformations causing the breakage of the stripper, resulting in a long-term blockage of the production line.

[0008] Thus, when the monitoring means detect that a lot of fiber dust has accumulated on the board between the needles, the user, or automatically, the control system of the installation, can intervene to clean the gaps on the board between the needles before a long-term blockage of the line occurs, and the flow rate and / or the rate of the needling line is thus greatly improved.

[0009] According to an advantageous embodiment, the installation further comprises a stripper plate which is pierced with a field of through holes and which is crossed by the needles before they penetrate the web or the sheet of fibers and the means for monitoring the quantity of accumulated fiber dust comprise means for monitoring, in particular for measuring, the vibrations and / or deformations of the stripper plate.

[0010] According to a first advantageous embodiment, the means for monitoring, in particular for measuring, the vibrations and / or deformations of the stripper plate comprise an accelerometer sensor, in particular arranged on the stripper plate.

[0011] According to another favorable embodiment, the means for monitoring, in particular for measuring, the vibrations and / or deformations of the stripper plate comprise means for monitoring, in particular for measuring, the stresses exerted on the fixing and / or support points of the stripper plate.

[0012] According to a first embodiment, the movement of the hands takes place along a rectilinear trajectory.

[0013] According to another embodiment, the movement of the hands takes place along an elliptical trajectory.

[0014] According to an improvement, alert means are provided capable of giving an alert when the quantity of accumulated fibre dust monitored, in particular the thickness of the layer of accumulated fibre dust monitored, in particular measured, exceeds a threshold value determined in advance.

[0015] In particular, the installation comprises a stripper plate which is pierced with a field of through holes and which is crossed by the needles before they penetrate the veil or the sheet of fibers and the alert means give the alert when the difference between the vibrations and / or deformations monitored over time and the vibrations and / or deformations when empty exceeds a threshold value determined in advance.

[0016] According to a preferred embodiment of the invention, the means for monitoring the vibrations and / or deformations of the stripper plate measure the deformations and / or vibrations of the stripper plate when empty, called reference vibration and / or deformation, corresponding to the case where no fiber dust is present between the needles, and comparison means are provided capable of comparing the vibrations and / or deformations of the stripper plate measured by the monitoring means over time with the reference vibrations and / or deformations.

[0017] According to an improvement, means are provided for removing fiber dust from the board between the needles.

[0018] In particular, control means, in particular electronic, may be provided which actuate the warning means and / or the dust elimination means when it is detected that the quantity of fiber dust, in particular the thickness of the layer of fiber dust, exceeds a threshold value determined in advance, in particular when a variation in the vibrations and / or deformations of the stripper plate is detected, in particular when they exceed a threshold value.

[0019] According to another embodiment, the monitoring means comprise a camera, in particular an electronic camera, which monitors the quantity of fiber dust, in particular the thickness of the layer of dust, formed on the board between the needles.

[0020] According to yet another embodiment, the monitoring means comprise a camera, in particular an electronic camera, which monitors the deformations and / or vibrations of the stripper plate.

[0021] The present invention also relates to a method of operating a needling machine installation comprising a needle board comprising a field of needles and means for driving the needles in a back and forth movement, in particular in the vertical direction, so that the needles, in one direction of movement, penetrate into a web or sheet of fibers, in particular non-woven, to pass through it in a transverse direction, in particular perpendicular, to the direction in which the web or sheet of fibers moves in front of the needles, then in a second direction of movement, emerge from the sheet or sheet of fibers, a quantity of accumulated fiber dust being present on the board between the needles, in which: the amount of accumulated fiber dust present on the board between the needles is monitored, and when the monitored amount of accumulated fiber dust exceeds a threshold value, means are implemented for removing the accumulated fiber dust from the board.

[0022] According to one embodiment, the implementation of the elimination means is carried out after stopping the operation of the installation.

[0023] According to another embodiment, the implementation of the elimination means is carried out automatically, without stopping the operation of the installation.

[0024] By way of example, an embodiment of the invention will now be described with reference to the drawings, in which: There figure 1 is a schematic side view of an installation according to the invention; The figure 2 is a schematic side view of another embodiment of an installation according to the invention; The figure 3 is a schematic side view of yet another embodiment of an installation according to the invention; and The figure 4 is a schematic side view of yet another embodiment of an installation according to the invention.

[0025] To the figure 1 , a needling installation comprises a board 1, from a lower face of which protrude needles 2 arranged according to a field of needles which is conventionally produced according to a so-called random or quasi-random pattern, the definition of random or quasi-random being well known in the field.

[0026] A vertical column 3 is integral with the needle board and transmits to it a back and forth movement which is imparted to it by a connecting rod and crank system (not shown in the figures), the drive of column 3 being carried out in the figure so as to have a vertical back and forth movement. However, a different drive system could be provided, in particular ensuring that the needles have a movement following an elliptical trajectory, for example by providing additional drive means in a transverse direction also giving the needles a transverse displacement component to thus achieve an elliptical trajectory of the needles.

[0027] A veil 5 or a sheet of fibers, in particular non-woven, moves in a horizontal direction, called the feed direction, or MD (Machine Direction) in front of the needles.

[0028] Support means, in particular in the form of a support table 6, support the veil or the tablecloth during its movement, the support table 6 being able in particular to be pierced with holes in correspondence with the needles.

[0029] A stripper plate 8, for example in the form of a sheet metal, pierced with through holes in a pattern corresponding to that of the needles, is arranged between the needle board 1 and the web or the fiber sheet. In particular, the through holes of the stripper correspond to the holes drilled in the support table 6. The needles, as is conventional in the field, have barbs.

[0030] An accelerometer sensor 9 is arranged integral with the plate 8 and makes it possible to measure the acceleration of the plate 8 forming a stripper in order to thus determine the vibrations and / or deformations undergone by this plate.

[0031] This accelerometer 9 is connected to an electronic control system 10 which makes it possible to display in particular the measurements taken by the accelerometer 9.

[0032] Furthermore, the electronic control system 10 comprises storage means capable of storing the measurements of the accelerometer 9, in particular when no dust is present between the needles on the underside of the board. The electronic control system 10 further comprises comparison means capable of comparing the measurements of the sensor 9 over time and so-called reference measurements corresponding to the measurement made by the sensor when no dust is present between the needles on the underside of the board. Thus, by measuring the deformations and / or vibrations of the stripper plate, the accelerometer allows the user to monitor the thickness of the layer of fiber dust that has accumulated on the board between the needles and thus to know when this thickness becomes too great to the point of threatening the installation with a long-term blockage due to the breakage of some of its components.

[0033] The control system 10 may further comprise alert means capable of issuing an alert, for example audible, visual or similar, to the user when the difference obtained from the comparison means varies, in particular when it exceeds a threshold determined in advance.

[0034] Following this alert, the user can intervene on the needle board to clean it, thus preventing a jam from causing the breakage of machine components, which is likely to result in a line restart time much longer than the time required for a stoppage simply to get rid of the fiber dust.

[0035] Means for removing the clumps of fiber dust may be provided, for example in the form of a blower 11 arranged to send a jet of air between the needles.

[0036] These elimination means can be activated by the user when an alert is issued. It is also possible to provide that the control system 10 triggers the elimination means when the difference value from the comparison means varies, in particular exceeds a threshold value set in advance.

[0037] To the figure 2 , another embodiment according to the invention is shown, in which means for fixing the stripper plate 8 in the form of rods and / or bearings 12 are connected to strain gauges 13 which measure the forces applied at these fixing points of the stripper plate.

[0038] Following the same principle as in the embodiment of the figure 1 , knowing that these two monitoring devices can also be combined to form a third embodiment, the strain gauges, initially, measure the force applied when there is no dust on the underside of the board 1, then the force applied over time, and send their measurement to an electronic control system which performs on these measurements the same processing as that performed by the system 10 on the measurements made by the accelerometer in the first embodiment. In particular, it is possible to provide, in this embodiment, comparison means, alert means and / or means for eliminating fiber dust as in the first embodiment.

[0039] According to the invention, embodiments have been described in which strain gauges and / or an accelerometer are used to determine the deformations and / or vibrations of the stripper plate.

[0040] However, of course, without departing from the scope of the invention, other systems could be used, in particular an electronic camera, a laser meter or any other means of monitoring the thickness of the layer of fiber dust accumulated on the board between the needles. It is also possible to measure with an electronic camera, a laser meter or the like, the vibrations and / or deformations of the plate, and thus carry out monitoring of the quantity of fiber dust clumps, in particular the corresponding thickness.

[0041] So, at the figure 3 , an embodiment is shown in which a camera 15 records the vibrations and / or deformations of the plate 8 and sends them to the system 10, which, depending on the recorded values, and in particular their variation beyond a threshold value determined in advance, triggers an alert and / or triggers a procedure either manually for eliminating the accumulated dust, in particular by briefly stopping the line, or automatically by actuating means for eliminating the dust clumps.

[0042] As for the embodiment shown in the figure 4, which can be implemented with or without a stripper plate, a camera 16 records the thickness of the layer of dust which accumulates between the needles on the underside of the board and sends this information to the system 10, which, in the same way as in the other embodiments, when the value of the thickness varies beyond a threshold value, triggers either a manual procedure for eliminating the accumulated dust, in particular by briefly stopping the line, or an automatic procedure by actuating dust elimination means.

Claims

1. Method for operating an installation forming a needle loom comprising a needle board (1) comprising a needle area and means (3) for driving the needles in a back-and-forth movement, in particular in the vertical direction, such that the needles, in one movement direction, penetrate a web (5) or lap of fibres, in particular nonwoven, to cross it in a direction that is transverse, in particular perpendicular, with respect to the direction in which the web or lap of fibres moves in front of the needles, then, in a second movement direction, leave the web or lap of fibres, a quantity of accumulated fibre dust being present on the board between the needles, in which : - the quantity of accumulated fibre dust present on the board between the needles is monitored (9; 13; 15; 16), and - if the quantity of fibre dust monitored exceeds a threshold value, means of removing the accumulated fibre dust on the board are put into operation.

2. Method according to claim 1, characterised in that the web or lap of fibres is supported as it moves in front of the needles by a support table (6).

3. Method according to either claim 1 or claim 2, characterised in that the installation comprises a plate (8) forming a stripper which is pierced by an area of through holes and which is passed through by the needles before they penetrate the web or lap of fibres.

4. Method according to claim 3, characterised in that the means of monitoring the quantity of accumulated fibre dust on the board between the needles comprise means (9; 13; 15) of monitoring vibrations and / or deformations of the plate forming the stripper.

5. Method according to claim 4, characterised in that the means of monitoring vibrations and / or deformations of the plate forming a stripper comprise an accelerometer sensor (9)6. Method according to either claim 4 or claim 5, characterised in that the means of monitoring vibrations and / or deformations of the plate forming a stripper comprise means (13) of monitoring the stresses exerted on the fixing and / or support points (12) of the plate forming a stripper.

7. Method according to any of claims 1 to 6, characterised in that warning means are provided, said means being suitable for raising the alarm when the quantity of accumulated fibre dust on the board between the needles exceeds a threshold value set in advance.

8. Method according to claim 7, characterised in that the warning means raise the alarm if the difference between the vibrations and / or deformations monitored over time and the vibrations and / or deformations in the unloaded state exceeds a threshold value set in advance.

9. Method according to either claim 7 or claim 8, characterised in that control means (10) are provided, in particular electronic control means, which actuate the warning means and / or means for removing the piles of fibres when it has been detected that the quantity of accumulated fibre dust exceeds a threshold value set in advance, in particular if a change in the vibrations and / or deformations of the plate forming a stripper is detected, in particular if these exceed a threshold value.

10. Method according to any of the preceding claims, characterised in that the movement of the needles takes place according to a rectilinear trajectory.

11. Method according to any of claims 1 to 9, characterised in that the movement of the needles takes place according to an elliptical trajectory.

12. Installation implementing the method according to any of the preceding claims.

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