EP0924329B1 - Device and process for needling nonwoven fabrics to produce an insulation mat - Google Patents

Abstract

The non-woven (10) is produced between upper and lower plates (14,16) using reciprocating needles (20) with upward acting barbs (22). The openings (19) in the upper plate are larger than the maximum needle width, preferably in the form of a recess (18) with a hole (18a) for the needle (20). An Independent claim is also included for the process of needle-punching with this arrangement where the fibers held in the needles during the upward stroke do not come into contact with the upper plate (14).

Description

The invention relates to a method and a device for needling nonwovens to produce an insulating mat.

Generic methods and devices are for example known from EP 0 296 970 A1 and EP 0 648 286 B1.

In the device according to EP 0 296 970 A1, needles are used used, which have barbs in the insertion direction the needles are aligned in the nonwoven fabric. With such Needles can only be made of high density non-woven fabrics because the barbs make the fiber structure strong compress.

The needling of voluminous fleeces prepares special ones Problems. As mentioned, the known technique can be very compact nonwovens can be produced with a high density; however, these fleeces can only be used in a thickness of a few millimeters. To nonwovens of greater thickness to manufacture, several nonwovens must be placed on top of each other become. This requires additional procedural steps and it remains the disadvantage of the high density that is just for Isolation is undesirable.

In addition to the needles mentioned above, there are also so-called Reverse needles are known whose barbs are in reverse Direction are arranged. The fibers are only at Pulling the needles out of the fleece "matted". The fleece is not compressed in this process, but against a hold-down device (also called a wiper) so ensure a constant thickness of the fleece and a Fraying in the surface area (when pulling out the To avoid needles).

The thickness of the product is the distance of the Hold-down and the needle length limited.

A disadvantage of these needles is that they are often too "Constipation" is coming. When pulling out the needles again and again pulled fibers out of the fleece, the mainly around the clamping or transition shaft of the needles. Build up over time these fibers between the needle board and stripper into one Felt that is difficult to remove and on the other hand to an irregular product quality leads.

This is the object of the invention based on a device and a method for needling To offer nonwoven fabrics for the production of an insulation mat, the the production of voluminous insulation boards with less Allow density.

The invention is based on the following knowledge:

Basically, they are suitable for the production of insulation mats low density especially the reverse needles mentioned. It cannot be prevented that the reverse needles, when pulled out of the fiber mat, fibers "take". Such fibers often hang like a loop on the barbs of the needles.

Now you create adjacent to the surface of the fiber mat a "free space" so that the needles (with the attached Fibers) without additional mechanical stress from the Nonwoven can be led out, so this leads to then returning the needles to the nonwoven an independent release of the attached fibers from the Barb, because parallel to the backward movement of the needles Fiber fleece in the direction of transport (perpendicular to the orientation the needles) is moved on. So the fibers are "Unthreaded".

Accordingly, the basic idea of the invention is the hold-down devices necessary for guiding the nonwoven fabric to adapt so that when the needles are removed there is no stripping effect as in the prior art is intentionally intended. This is surprisingly successful simple way that the or the hold-down in the areas in which the needles are held down by the hold-down device are passed through, have correspondingly large openings, which prevent the above-mentioned stripping effect.

• zwei flächenförmige Niederhalter, die im Abstand zueinander angeordnet sind, wobei der Abstand in etwa der Vliesdicke entspricht,
• mindestens ein Niederhalter weist mindestens eine Öffnung auf,
• mindestens eine Nadel ist an einer Tragvorrichtung so geführt, daß sie alternierend durch die Öffnung in das Faservlies und aus diesem heraus bewegt werden kann,
• die Nadel weist eine Länge auf, die größer als ihr maximaler Hub ist und umfaßt an ihrem, in das Faservlies eindringenden Abschnitt mindestens einen, entgegen der Einsteckrichtung der Nadel verlaufenden Widerhaken,
• die Öffnung ist größer als die maximale Breite der Nadel im Bereich des/der Widerhaken(s).

Accordingly, in its most general embodiment, the invention relates to a device for needling nonwoven fabrics for producing an insulating mat with the following features:

• two flat hold-down devices, which are arranged at a distance from each other, the distance approximately corresponding to the fleece thickness,
• at least one hold-down device has at least one opening,
• at least one needle is guided on a carrying device such that it can be moved alternately through the opening into and out of the nonwoven fabric,
• the needle has a length which is greater than its maximum stroke and comprises at its portion penetrating into the nonwoven fabric at least one barb which runs counter to the insertion direction of the needle,
• the opening is larger than the maximum width of the needle in the area of the barb (s).

The carrying device can be used with a large number of Needles are designed that are spaced apart extend over the entire width of the nonwoven. The Carrier device as such is from the prior art known, and is mostly referred to as "needle board", the needles on a mostly rectangular base in "rows" and "columns" side by side with about are arranged at the same distance.

In the device described, each needle can corresponding opening in the hold-down assigned become.

In contrast, it is easier if several needles, in extreme cases all needles, a common opening in the hold-down device is assigned. In any case, this represents a "free Mobility "of the needles in relation to the corresponding one Hold-down device safely and also creates the conditions for adhering fibers freely (partially) from the Fiber mat can be pulled out to return after return the needles from the needles again and thus fall back to the surface of the nonwoven where they in the further course between the flat downholders back into the nonwoven or the fiber mat to get integrated.

In the latter embodiment, is only ensure that the remaining surface sections of the hold-down device are sufficient, the assembly of the To ensure fiber fleece, so ensure that the nonwoven or the one formed therefrom Insulation mat with constant thickness after passing through the hold-down device into the further production stages can.

One embodiment of the device provides for the opening of the hold-down device from an outwardly projecting form box-shaped section in which at least one Through opening for the needle (s) is arranged.

This results in corresponding "box-shaped Recesses "in the area of the hold-down device compared to the corresponding surface of the nonwoven into which the Fibers that are pulled out of the fleece are guided be on before proceeding further in the process the described way released from the needles become. This embodiment is in the attached Description of the figures explained in more detail.

In addition, the device can, for example, with a Carrier be designed with an adjustable stroke to so the fiber fleece is targeted continuously or in certain areas needles (to felt).

• Das Faservlies wird einer aus zwei beabstandet zueinander angeordneten flächenförmigen Niederhaltern bestehenden Formgebungseinrichtung zugeführt und durch diese hindurchgeführt,
• auf dem Weg durch die Formgebungseinrichtung werden Nadeln durch (eine) entsprechende Öffnung(en) mindestens eines Niederhalters in das Faservlies eingeführt, wobei die Nadeln jeweils mindestens einen, entgegen der Einführrichtung der Nadeln verlaufenden Widerhaken aufweisen,
• die Nadeln werden nach Erreichen ihres Maximalhubs wieder aus dem Faservlies herausgezogen, wobei
• die Nadeln sowie gegebenenfalls von den Nadeln mitgeführte Fasern mit dem Niederhalter nicht in Berührung kommen.

The most general embodiment of the method according to the invention is characterized by the following features:

• The nonwoven fabric is fed to a shaping device consisting of two sheet-like hold-down devices which are arranged at a distance from one another and is guided through it,
• on the way through the shaping device, needles are introduced into the fiber fleece through (a) corresponding opening (s) of at least one hold-down device, the needles each having at least one barb that runs counter to the direction of insertion of the needles,
• After reaching their maximum stroke, the needles are pulled out of the nonwoven again, whereby
• the needles and any fibers carried by the needles do not come into contact with the hold-down device.

Depending on whether needling on one or both sides is desired, one or both hold-downs on the described way designed and the nonwoven either treated on one or both sides in the form mentioned become.

According to one embodiment, the needles should be so far be moved out of the nonwoven that you free end slightly above a corresponding one Surface of the nonwoven is arranged before the Needles are returned to the nonwoven. On this ensures that entrained fibers in usually only be partially pulled out and not detach completely from the fiber composite. Can accordingly the fibers are also easier after the needles are returned (and parallel loosening of the attached fibers) back into the Fiber composite back, for example by subsequent surface sections of the hold-down on the Surface to be pushed back.

According to the above embodiment of the The method can also be designed in such a way that that the needles are clocked in and out of the nonwoven fabric the nonwoven are moved out.

With regard to the transport of the nonwoven fabric, it turns out as appropriate, the nonwoven continuously through the To lead shaping device. That way it will Loosening of fibers carried by the needles due to the relative displacement of the nonwoven the "stationary" needles.

Further features of the invention result from the Characteristics of the subclaims and the other Application documents.

The invention is described below using an exemplary embodiment explained in more detail.

The figures show - in a highly schematic representation - A partial view of an inventive Device in two successive production phases.

An approximately 30 mm thick mineral fiber fleece 10 is closed in FIG recognize which is transported in the direction of arrow T. It passes through a shaping device 12, which consists of two hold-downs 14, 16, which are parallel at a distance of 30 mm (corresponding to the thickness of the nonwoven fabric 10) are arranged.

14v, 16v are at their front end in the transport direction the hold-down devices 14, 16 are angled outwards, so that there is a kind of funnel shape over which the Nonwoven fabric 10 is fed to the shaping device 12. The originally even more voluminous non-woven material becomes slightly pre-compressed to the desired material thickness (here: 30 mm), to get the necessary strength.

While the lower hold-down device 16 is flat overall is, the upper hold-down device 14 has a box-like Return 18 to form a cavity (Opening) 19 so that a partial surface 10t of the Nonwoven fabric 10, when it passes through the recess 18, is not supported by the hold-down device 14.

The box-shaped recess 18 has in its outer Base 18g an opening 18o through which a so-called Reverse needle 20 is guided at its free lower end has a barb 22 which slopes obliquely runs above.

The needle 20 is attached to a needle bar 24 which Is part of a lifting device for the needle 20. The length the needle 20 is greater than the maximum stroke of the needle 20. Da both the needle bar 24 and the lifting device for State of the art and for example in EP 0 648 286 B1 are described to that extent Explanations are referenced.

The device works as follows:

The nonwoven fabric 10 is in the transport direction T through the Shaping device 12 performed. The needle is cycled 20 perpendicular to the surface 10o of the nonwoven fabric 10 in the Fleece 10 moved in and then led out again. On the way back, the barb 22 causes the Needle 20 a needling (felting) of the fibers within of the fleece 10. When pulling the needle 20 out of the Nonwoven fabric 10 can happen that individual fibers get caught on barb 22, as shown in FIG is (loop 10s).

During the pulling out of the needle 20 the nonwoven becomes 10 continuously moved (this position is also in Figure 1 shown), so that the subsequent return the needle 20 in the nonwoven fabric 10 on the barb 22 attached fiber loop 10s automatically from Barb 22 releases again and in the further course of the Shaping device 12 from the hold-down device 14 again the surface 10o of the fleece 10 is returned.

FIG. 2 shows a production phase in which the needle 20 has already been returned by a section and the fiber loop has come off the barb 22.

In order to return the detached fiber loop 10s in the surface 10o of the fleece 10 without loss of quality ensure the front wall in the direction of transport 18v of the box-shaped element 18 a rounded Have transition area 18a, as shown in Figure 2.

It goes without saying that the device usually not a needle, but a variety of Has needles on a corresponding needle board. Out For better clarity is in the figures however only one needle is shown.

The insulating mat leaving the shaping device 12 becomes then supplied to the usual further process stages.

Claims (9)

1. A device for needling fibrous webs (10) used in the manufacture of an insulating mat, wherein said device has the following characteristics:

   1.1 two planiform holding-down appliances (14, 16) that are spaced apart from one another by a distance that approximately corresponds to the thickness of the web,

   1.2 at least one holding-down appliance (14) contains at least one opening (19),

   1.3 at least one needle (20) is guided on a carrying device (24) in such a way that it can be alternately inserted into the fibrous web (10) and retracted from the fibrous web (10) through the opening (19),

   1.4 the needle (20) has a length that is longer than its maximum travel and comprises at least one barb (22) that extends opposite to the inserting direction of the needle (20) on its section that penetrates into the fibrous web (10),

   1.5 the opening (19) is larger than the maximum width of the needle (20) in the region of the barb(s) (22) and

   1.6 is formed by an outwardly projecting, box-shaped section (18) in which at least one clearance opening (18o) for the needle(s) (20) is arranged.
2. The device according to Claim 1, wherein the carrying device (24) is realized with a series of needles (20) that are spaced apart from one another and extend over the entire width of the fibrous web (10).
3. The device according to Claim 2, wherein a corresponding opening (19) in the holding-down appliance (14) is assigned to each needle (20).
4. The device according to Claim 2, wherein a common opening (19) in the holding-down appliance (14) is assigned to several needles (20).
5. The device according to Claim 1, comprising a carrying device (24) with adjustable travel.
6. A method for needling fibrous webs used in the manufacture of an insulating mat, wherein said method has the following characteristics:

   6.1 the fibrous web is transported to and guided through a forming device that consists of two planiform holding-down appliances that are spaced apart from one another,

   6.2 during the passage through the forming device, needles are inserted into the fibrous web through (a) corresponding opening(s) in at least one holding-down appliance, wherein the needles respectively contain at least one barb that extends opposite to the inserting direction of the needles, and

   6.3 the needles are retracted from the fibrous web after their maximum travel is reached, wherein

   6.4 the needles, as well as fibers that might be carried along by the needles, do not come in contact with the holding-down appliance.
7. The method according to Claim 6, wherein the needles are retracted from the fibrous web to such a degree that their free end is situated slightly above the corresponding surface of the fibrous web before the needles are reinserted into the fibrous web.
8. The method according to Claim 6, wherein the needles are inserted into the fibrous web and retracted from the fibrous web in a cyclic fashion.
9. The method according to Claim 6, wherein the fibrous web is continuously transported through the forming device.

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