Method and apparatus for manufacturing net material and other non-woven fabrics

[57] ABSTRACT

An apparatus for producing and subsequently longitudinal slitting of a hose-like fabric consisting of a plurality of parallel warp threads and two continuous weft threads intersecting the warp threads and bonded thereto at points of intersection, comprises means for advancing the warp threads in the form of a hollow-cylindrical thread layer, and means for advancing a weft thread from each of two stationary weft thread supplies to a respective one of two weft thread guides rotating on a common axis parallel to the axis of the warp thread layer, the weft thread advancing means being arranged so that the weft threads enter the respective thread guides from axially opposite ends of the hollow warp thread layer.

Claims, 1 Drawing Figure

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Patented May 16, 1972

3,663,331

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INVENTOR ε-I^IK S0LBEC 1$

BY ^f ATTORNEYS

3,663,331 ¹ 2

METHOD AND APPARATUS FOR MANUFACTURING NET MATERIAL AND OTHER NON-WOVEN FABRICS

BACKGROUND OF THE INVENTION

The present invention relates to a method for manufacture “ of net material and other non-woven fabrics, comprising advancing several parallel or wrap threads arranged in a hollow cylindrical layer of threads, helically laying two transverse or weft threads, each supplied from a separate supply, on one face of the layer of warp threads, securing the warp and the *' weft threads to each other at the points of intersection ofthe threads, and slitting the hose fabric thus formed.

In known methods of this kind, the weft or transverse threads are supplied from spools mounted on a ring rotating j« around the axis of the layer of warp threads. The ring is in itself relatively bulky, which renders it necessary to keep the number of revolutions of the ring low. A further factor limiting the permissible number of revolutions of the ring is the unbalance ofthe ring which, inevitably, occurs in practice due to 2( the fact that the individual spools of thread never have exactly the same mass. The number of revolutions directly determines the speed at which the longitudinal threads can be advanced and, thereby, the rate of production which, thus, also becomes relatively low. The necessity of stopping the machine each 25 time a spool is empty, is a contributory factor to the low production rate.

BRIEF SUMMARY OF THE INVENTION

According to the invention, the two transverse or weft threads are supplied from stationarily mounted supplies and are fed to the place of laying from opposite ends ofthe layer of warp threads, and one of the weft threads is advanced on the inside of said layer.

As compared to the known methods dealt with above, the invention has the advantage that the transverse or weft threads may be laid at a considerably higher speed since the thread guides employed for this purpose can be constructed as very light arms which do not have to carry any supply of thread 40 rotating therewith, and it will consequently be possible to increase the rate of production of the fabric manufactured considerably. Compared with the other known methods, in which a single transverse thread is laid with a rotating thread guide, a doubling of the rate of production is achieved based on the 45 unexpected fact that two threads from stationary supplies can be laid simultaneously around the warp thread layer without interfering with each other or with the associated thread guides, provided that they are fed to the place of laying in axially opposite directions. The use of stationary thread supplies ⁵⁰possesses the additional advantage that the manufacturing process must not be stopped each time a supply spool is empty, since it is possible, in advance, to tie the leading end ofthe thread from a fresh spool to the end of the thread from the spool being unreeled; it will also be possible to make use of arbitrarily big spools, so that the tending or supervision of the apparatus during its operation is reduced to a minimum.

The invention also relates to an apparatus for performing the method, which apparatus has means for feeding a plurality of parallel warp threads which together form a hollow cylin- ⁶⁰drical layer of threads,in the longitudinal direction of the threads, two thread guides rotating around an axis parallel to the layer of threads for helically laying two transverse or weft threads, each fed from a separate supply, on one side of the ¢5 thread layer, means for securing the warp and the weft threads to each other at their points of intersection and means for slitting the hose fabric thus formed. The advantages pointed out above are obtained in the apparatus according to the invention by mounting the two weft threads supplies stationaryly 70 and by leading the weft threads from the respective supplies to the associated thread guides from opposite ends ofthe hollow cylindrical layer of warp threads internally of the rotating thread guide and internally of the warp thread layer, respectively. 75

In a structurally simple embodiment of the apparatus the two thread guides are secured to a common rotating carrying member. The thread guides may then be mounted diametrically opposite each other on the carrying member, which makes it easy to obtain perfect dynamic balancing of the carrying member and, consequently, operate the apparatus with high laying speed of the transverse threads.

BRIEF DESCRIPTION OF THE DRAWING &gt;

The single FIGURE of the accompanying drawing illustrates in a somewhat diagrammatical way an apparatus embodying the present invention in lateral elevation, partly in section, whereby only those component parts of the apparatus which are deemed necessary for the understanding of the invention are shown.

DETAILED DESCRIPTION

The apparatus illustrated on the drawing has a base 1 carrying a frame comprising four columns 2 which, at their top ends, are connected with each other by a frame member 3. As shown, the columns may, in addition, be connected with each other some distance above the base by means of a second frame member 4. An annular supporting cylinder 5 for the net material being manufactured in the apparatus is carried by the intermediate frame member 4 by means of two columns 6 and by horizontal braces 7, of which the drawing shows one.

The cylinder 5 may contain means, not shown, for locally heating and/or cooling the cylinder surface with a view to softening and subsequent hardening of the adhesive employed in the production of net material.

On or beside the base of the machine there is provided a plurality of spools, not shown, which each contains one of the warp threads forming part of the finished net material. The warp threads, which are designated by 8 in the drawing, extend through guiding means, not shown, upwardly on the inside of the supporting cylinder 5 and across the upper edge thereof, which may be provided with grooves, guiding combs or other means for ensuring a predetermined distribution of the warp threads along the outer circumference of the cylinder. The warp threads 8 are subsequently fed downwards on the outer side of the cylinder 5 and, by means of a mechanism described below, two transverse or weft threads 9 and 10 are laid helically onto the outer side of the parallel warp threads. The connection between the warp and weft threads at their points of intersection can be effected by means of an adhesive which, in a manner not shown in greater detail, can be applied to one or the other thread system either prior to the laying of the weft threads or in connection therewith. When using thermoplastic threads, it may in certain cases be possible to dispense with a separate adhesive, in that the interconnection can be effected by heating the threads either on the cylinder 5 or by means of heating members mounted outside the cylinder. An apparatus for producing net material by the method generally outlined above is described in U.S. Pat. No. 3,384,521. In the known apparatus, only one weft thread is employed.

As shown, the apparatus has a rotating member 11 for laying the two weft threads 9 and 10, which member is rotatably journalled in the apparatus. This is schematically represented in the drawing by a cross bar 12 extending between the two columns 2 shown and having bearing means, not shown, for the rotating member 11. The rotation of the member 11 can be effected by any suitable means, e.g., as indicated by means of a tooth gear 13, which is integral with member 11 and driven through a pinion from a motor, not shown, on the frame of the apparatus.

The carrying member 11 is hollow and from a spool 14 standing on the base of the apparatus one weft thread 9 extends over stationary guide means IS which, in the embodiment shown, consist of rollers, but which could be of any suitable shape. From a guide means 25 constructed as an eye and placed immediately above the carrying member 11, the

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4 weft thread 9 proceeds through the hollow carrying member and further through guide means 16 on the rotating carrying member 11. The guide means 16 are shown as eyes, but they could be of any other suitable shape. The last guide means 16 is located close to the supporting cylinder 5. From a stationary 5 spool 17 similar to the spool 14 and mounted on the base 1 of the apparatus, the other weft thread 10 extends upwards internally of the stationary supporting cylinder 5. As indicated, the thread 10 may be guided in guide bushings 18, secured to the upper brace 7 and a lower brace 19, respectively. From the 1° topmost bushing 18, the thread 10 passes across the roundedoff edge of the bushing and further through guide means 21 on the rotating carrying member 11. The guide means 21 are shown as eyes similar to the means 16, and the last eye 21 lays the thread 10 around the warp threads 8 advancing along the cylinder 5, by preference midway between the windings formed of the other weft thread 9. When the two guide means are located diametrically opposite each other and at the same level, this mutual placing of the two weft threads is theoretically always obtained but, if desired, one of the two guide ²⁰means may be adjustable axially or circumferentially to permit a fine adjustment of the mesh width. Such an adjustability may also become expedient if the two said guide means are not mounted diametrically opposite each other but at the same _9&lt;side of the axis of rotation of the carrying member.

In order to reduce the mass of the rotating means to the greatest possible extent, it may be expedient to construct the carrying member 11 as two radial arms secured to a hollow hub, by means of which the carrying member is supported in jq the apparatus and driven by it driving motor. Alternatively, the carrying member could, however, also be constructed as a cup-shaped cylinder.

The net material formed by laying the weft threads 9 and 10 across the warp threads 8 and subsequently securing them 35 thereto, is slit into two nets following the hardening or solidification of the adhesive, which is effected by means of schematically indicated cutting means 11 fitted diametrically opposite each other underneath the cylinder 5. These cutting means may, in a known manner, consist of heated knives or 40 wires which, by melting the successive weft threads, cause them to break. The two nets thus formed may be pulled over suitable guide means, not shown, which assist in flattening the nets, whereupon they are removed from the apparatus via separate discharge rollers 23 to take-up rollers, not shown. 45

Since the two supply spools 14 and 17 for the weft threads are stationary, it will be possible to let the carrying member 11 with the thread guides rotate at a high speed, as mentioned earlier, and, as indicated in the drawing, the ends of the threads 24 on the two spools will normally be accessible, so 50 that during the operation of the machine it will be possible to tie the leading thread end from a fresh spool, not shown, to the respective thread end 24, so that the operation of the apparatus can go on continuously without having to stop for changing spools. 55

In the drawing, the apparatus is shown with a vertical orientation of the supporting cylinder 5, but the invention may be utilized to the same advantage in an apparatus, in which the weft threads are wound around a layer of warp threads extending with a horizontal or inclined axis. It is also possible to slit the hose fabric axially at one location only or at more than two locations along its circumference. It will also be realized that the mesh size in the fabric produced may be chosen arbitrary and the mesh width may be so small that the fabric produced may have the character of a normal closely woven textile fabric having intersecting warp and weft threads.