EP2999814B1

EP2999814B1 - Warp knit net, method of making same and apparatus therefore

Info

Publication number: EP2999814B1
Application number: EP13745908.7A
Authority: EP
Inventors: Enrico RIBOLA; Igor RIBOLA
Original assignee: Retificio Ribola Giovanni SNC
Current assignee: Retificio Ribola SNC Di Ribola Enrico Igor E C
Priority date: 2013-05-20
Filing date: 2013-05-20
Publication date: 2019-09-11
Anticipated expiration: 2033-05-20
Also published as: EP2999814A1; WO2014188455A1

Description

The present invention relates to a warp knit net, e.g. a fishing net, a method for manufacturing a warp knit net and a warp knitting machine for making same.
As is well known, the warp knit net constitutes knitting, and in particular warp knitting. The knit fabric that forms a net, unlike the fabric formed by the weaving of two elements (weft and warp), is formed by a single element that works on itself, i.e. knitting each wale with the preceding one and with the subsequent one.
Thus in the net, as in the other warp knit fabrics, a series of warp yarns forms the loops simultaneously. Each needle works with its own yarn and the primary interlacement obtained is called chain of loops.
Through a variable movement of the needles, the chains of loops are mutually linked in such a way as to form the meshes of the net. The junction point of the chains of loops is called "knot". There are also "knotless" nets, i.e. nets in which said "knot" is not an actual seaman-like knot but a mere interlacing of the chains of loops. US 3 389 582 discloses a warp knit textile fabric having a repetitive base net configuration including in the parallel wale of the base net, inlaid yarns that are alternated between adjacent wales in a repetitive pattern. US 5 339 657 discloses a warp knit net fabric according to the preamble of independent claims 1 and 7 in which the number of stitches in each leg and in each join of a diamond pattern is varied to vary the size of the openings defined by the legs.
Moreover, there are two types of "knot" in "knotless" nets: the simple knot and the so-called "superknot". The superknot is a particular type of binding interlacing of the chains of loops which enables to obtain a net with greater strength and higher weight than a net with simple knot.
The choice between the two knots enables to have nets with different characteristics. In particular, for equal number and type of yarns used in the warp knitting, the net with simple knot has a lower weight per square meter than the one manufactured with the super knot. However, the latter net has higher breaking strength than the one with the simple knot.
Strength is a very important factor in nets and in particular in safety nets and in fish farming cages, which may contain thousand of fish.
An object of the present invention is to propose a warp knit net having greater strength than a net of equal weight, or, for equal strength, having lower weight.
Said object is achieved with a warp knit net according to claim 1, with a method for warp knitting a net according to claim 10 and with a warp knitting machine according to claim 12. The dependent claims described preferred or advantageous embodiments of the net of the invention.
The characteristics and the advantages of the net of the invention shall be made readily apparent in the description that follows of some preferred embodiments thereof, provided purely by way of non limiting examples, with reference to the accompanying figures, in which:

Figure 1 is a view of some meshes of a net according to the invention;
Figure 2 shows the warp knitting scheme of the net in a first embodiment with eight reeds;
Figure 3 shows the warp knitting scheme with eight reeds, in a variant not according to the invention;
Figure 4 is a warp knitting scheme with three reeds;
Figure 5 shows an example of a portion of a chain of loops, with the interlacement exaggeratedly widened to illustrate the path of the yarn more clearly;
Figure 6 shows an example of a portion of a chain of loops, provided with a filling yarn, with the interlacement exaggeratedly widened to illustrate the path of the yarns more clearly;
Figure 7 shows an example of a portion of a chain of loops with reinforcing interlacement, with the interlacements exaggeratedly widened to illustrate the path of the yarns more clearly.

In said drawings, reference number 1 indicates a portion of a warp knit net according to the invention as a whole. The net comprises a plurality of net meshes 10, each of which is defined by a polygon with at least three sides and as many knots N which connect a net mesh to adjacent meshes.
In the remainder of the description, the term "chain of loops" 12 means the set of the yarns between two knots N of a net mesh, i.e. one side of the polygon which defines a mesh 10.
For simplicity of description, the term "yarn" means not only a single yarn, but also a group of yarns guided by a same reed and held by the same needle. In the warp knitting of the net, one or more yarns may be threaded in each needle of the mesh. The number and thickness of the yarns threaded into each needle determines the type of net, and in particular its thickness and weight. For simplicity, the term "yarn" shall be used both in the case in which a single yarn is threaded into a needle and in the case in which instead the net is obtained threading a plurality of yarns into each needle. Therefore, the group of yarns thus constituted, all threaded into the same needle, shall be called "yarn" as if the group of yarns constituted a single large yarn. The needles thus threaded are mounted on movable reeds which are comb-shaped elements, whose teeth are constituted by the aforesaid needles. In this way, the yarn threaded into a needle stands on the reed where the needle is positioned. The reed, when moving, also moves the needle in which a given yarn is threaded. For this reason the warp knitting schemes described below, which represent the movements of the yarns in a machine, are also representative of the movement of the reeds which bear the needles in which those yarns are threaded.
The term "knot" means any manner of junction between two chains of loops 12. As stated above, the term "knot" is also used to define a simple interlacement of chains of loops 12.
Figure 5 shows a simple chain of loops, in which at least a first yarn T1 forms a primary interlacement of the chain of loops 12, i.e. works on itself knitting each course with the preceding one and with the subsequent one. As shown in Figure 5, the first yarn T1 forms a row of mutually interlaced turns.
Figure 6 shows the simple chain of loops to which was added at least a second yarn T2, which passes through the primary interlacement of the chain of loops, in such a way as to lock the chain of loops itself and hence to prevent it from unraveling. Said second yarn T2 also serves as filling or core of the chain of loops. As shown in Figure 6, said second yarn passes through the turns formed by the first yarn T1.
According to a general aspect of the invention, in at least one portion of a chain of loops 12 of a net mesh, said second yarn T2 forms at least one reinforcing interlacement of the chain of loops.
Therefore, one aspect of the invention consists of the creation of an additional interlacement, defined reinforcing interlacement, within the chain of loops 12 for the purpose of reinforcing the net. It should be noted that while said interlacement, as described further on, preferably also involves the knot N of the net, does not necessarily constitute a modification of the type of knot of the net, but constitutes at least one modification of the chain 12. In other words, the needles of the knitting machine, in addition to creating the primary interlacement of the chain of loops, work in such a way as to create at least one additional, reinforcing interlacement within the chain of loops 12.
In a preferred embodiment, the reinforcing interlacement is carried out on at least one chain of loops without involving the other chains of loops of the mesh. In nets in which at least two chains of loops are joined or combined or placed mutually side by side, the reinforcing interlacement is carried out in at least one of the joined chains of loops.
The reinforcing interlacement can be carried out in any position along the chain of loops, but according to the invention it is carried out next to the knot N, possibly also connecting to the knot, reinforcing it and/or extending it. According to the invention a reinforcing interlacement is carried out before and immediately after a knot N.
Figure 7 shows a portion of chain of loops 12 with a reinforcing interlacement. A second yarn T3 is shown, which forms a similar interlacement to the primary interlacement shown in Figure 5 and, interlacing, it is also interlaced to the first yarn T1. Hence, the two interlacements are mutually concatenated. Note the difference between the filling yarn T2 shown in Figure 6 and the yarn T3 which forms the reinforcing interlacement: the former does not form an interlacement but it is simply held by the interlacement of the first yarn T1 when the concatenated turns of the first yarn are closed; the latter, instead, forms an actual interlacement which, in addition to concatenating its own turns, also interlaces the turns of the first yarn.
Figure 2 shows a warp knitting scheme of a net which uses eight reeds P1-P8, to which correspond as many threads (or groups of threads, as specified above). In the remainder of the description of the warp knitting scheme, therefore, the terms "reed" and "yarn" can be interchangeable, since the reeds move the yarns to obtain the required warp knitting scheme.
In a machine with eight reeds, the first two reeds P1 and P2 can be used, if provided, to produce the lateral finish of the net, known as "edge".
The third reed P3 and the fourth reed P4 form the primary interlacements of two chains of loops that are mutually interlaced. The yarns corresponding to the reeds P1-P4 are represented with a solid, thick line in Figure 2.
The fifth reed P5 and the sixth reed P6 form the reinforcing interlacements of two chains of loops that are mutually interlaced. The corresponding yarns are represented with a thinner solid line in Figure 2.
The seventh reed P7 and the eighth reed P8 form the filling or core of two chains of loops that are mutually interlaced. The corresponding yarns are represented with a dashed line in Figure 2.
Therefore, if the lateral finishes of the net are excluded, a chain of loops is formed by a first yarn T1 that forms the primary interlacement, by a second yarn T2 that forms the filling or core of the chain of loops, and by a third yarn T3 that forms the reinforcing interlacement.
With reference to the scheme of Figure 2, the pairs of chains of loops that are interlaced are thus formed respectively by the reeds P3, P5, P8 and by the reeds P4, P6, P7.
In the scheme of Figure 2, the interlacement of two adjacent chains of loops, which forms a knot, is represented in the area indicated as N.
As is readily apparent, in the example shown the third yarn T3 initially serves as a filling yarn, similarly to the second yarn T2. In proximity to the knot, the third yarn T3 instead forms the reinforcing interlacement. Said reinforcing interlacement also develops within the knot and continues at the exit of the knot and for an initial portion of the subsequent chain of loops.
As stated above, according to requirements the reinforcing interlacement may extend along the entire chain of loops or on a limited portion, which may also not be connected to the knot.
In one variant not according to the invention shown in Figure 3, the reinforcing interlacement extends along the entire chain of loops. In this figure, the reeds P1 and P2 form the edges of the net. The third reed P3 and the fourth reed P4 form the primary interlacements of two chains of loops that are mutually interlaced. The corresponding yarns are represented with a solid, thick line in Figure 3. The fifth reed P5 and the sixth reed P6 form the reinforcing interlacements of two chains of loops that are mutually interlaced. The corresponding yarns are represented with a thinner solid line in Figure 2.
The seventh reed P7 and the eighth reed P8 form the filling or core of two chains of loops that are mutually interlaced. The corresponding yarns are represented with a dashed line in Figure 3.
The scheme shown in Figure 4 shows a net with five meshes and three reeds (not considering the reeds P1 and P2 that form the edge). The third reed P3 and the fourth reed P4 form the primary interlacements of two chains of loops that are mutually interlaced. The corresponding yarns are represented with a solid, thick line in Figure 4. The fifth reed P5 forms the filling of a chain of loops and, in proximity to the knot N, it forms a reinforcing interlacement of said chain of loops. The corresponding yarn is represented with a thinner solid line in Figure 4.
Therefore, the net with a reinforcing interlacement can be obtained with a warp knitting machine having at least three reeds.
The warp knit net of the invention can be produced with a known warp knitting machine, comprising upper needles, born by the reeds, into which are threaded the yarns and which are movable laterally, lower needles, provided with hooks, movable vertically to engage and displace the yarns borne by the upper needles, sinkers and mechanical and/or electromechanical devices that actuate their movement according to the pre-set warp knitting scheme. For example, the reeds that support the upper needle-bearing yarns are actuated laterally by means of a chain of loops, some of whose links have a shape that determines the lateral displacement of the reeds. The lower needles are actuated vertically through respective actuating organs; e.g., the lower needles are fixed to a lower bar connected to cams that determine the rising and descending movements. Therefore, the formation of the net is given by the combined motion of the upper, yarn bearing needles and of the lower needles.
A mesh dragging organ, commonly known as "take-up", drags the net outside the set of the needles as soon as it is formed, in such a way as not to hinder the formation of new meshes.
To obtain the reinforcing interlacement starting from a filling thread, it is necessary to modify the movement of the needles, and thus of the reeds, which work said filling yarn in such a way as to allow it to interlace with the yarn that forms the primary interlacement.
In particular, it may be necessary to make some modifications to a known net warp knitting machine. For example, it will be necessary to modify the rise time of the lower bar connected to the cams. In particular, when the bar is in the raised position, the reeds that traverse it form an interlacement. When the bar is in the lowered position, the reeds form only the filling of a chain of loops. Normally, the bar is in the raised position only at the passage of the reeds that form the primary interlacement. To obtain the reinforcing interlacement, it will be necessary to extend the time in which the bar is in the raised position, closer to the reeds, in such a way as to enable at least one additional reed to traverse it and form the reinforcing interlacement.
In one embodiment of the warp knitting machine, it will also be necessary to modify the pulley or electric motor regulating the brakes. Moreover, it may be necessary to fit the machine with a more powerful main motor to facilitate operations. Additionally, it may be necessary to adapt the take-up organ to increase its power. In chain of loops machines, it may also be necessary to modify the links, or gliders, of the machine that laterally actuate the reeds.
Said different actuation of the needles to obtain the reinforcing interlacement may be obtained modifying the mechanical components used to raise the needles, or, if said actuation is provided by electromechanical actuators, with a different control logic of said actuators.
Hence, an object of the present invention is also a machine modified to actuate the needles that work the filling yarns in such a way that said needles operate, at least for a certain segment of the chain of loops, to form a secondary interlacement.
In other words, the method for manufacturing the net according to the invention entails the modification of the warp knitting scheme with respect to a traditional warp knitting scheme. To carry out said modification of the warp knitting scheme, the mechanical or electronic parts of the net warp knitting machine are adapted in such a way as to modify the movement of the needles that work the filling yarns in order to obtain, with said yarns, additional reinforcing interlacements with respect to the primary interlacements of the chains of loops.
Therefore, to obtain the reinforcing interlacement it is necessary for the movement of the needles and hence of the reeds of the mesh to be such that said needles and reeds, in addition to interlacing the chains of loops at the level of the knot also interlace the yarns within the chain of loops, without creating an interlacement with another chain of loops of the same net.
It should be noted that the reinforcing interlacement, in addition to improving the strength of the meshes of the net, enables to stop the rupture of the net. Usually, if the mesh breaks the chain of loops unravels all the way to the knot. The reinforcing interlacement, being formed within the chain of loops, causes the chain of loops not to unravel all the way to the knot, but the unraveling process stops at the level of the reinforcement.
To the embodiments of the warp knit net according to the invention, a person skilled in the art, to meet specific requirements, may make modifications, adaptations and replacements of elements with functionally equivalent ones, without departing from the scope of the following claims. Each of the characteristics described as belonging to a possible embodiment may be achieved independently of the other embodiments described.

Claims

Warp knit net, comprising a plurality of net meshes (10), each of which is defined by a polygon with at least three sides (12) and as many knots (N) which connect a net mesh to adjacent meshes, each side (12) being formed by a chain of loops comprising at least a first yarn (T1) that forms first yarn mutually interlaced turns so as to form a primary interlacement of the chain of loops, and at least a second yarn (T3) that passes through said primary interlacement of the chain of loops, characterized in that said second yarn (T3), in at least one portion of the chain of loops before and immediately after the knots (N) of the warp knit net forms second yarn (T3) mutually interlaced turns which are also interlaced with first yarn (T1) mutually interlaced turns of adjacent courses so as to form at least one reinforcing interlacement of the chain of loops.
Net according to the previous claim, wherein said reinforcing interlacement is obtained next to a knot.
Net according to claim 1 or 2, wherein said reinforcing interlacement develops also within the knot, independently of the type of knot of the net.
Net according to any of the previous claims, wherein said second yarn (T3) forms, within a chain of loops, in part the filling or core of the chain and in part the reinforcing interlacement.
Net according to any of the previous claims, comprising at least an additional third yarn (T2) serving as filling or core of the chain of loops.
Net according to any of the previous claims, wherein the knots of the meshes are obtained as interlacements of two chains of loops.
Method for manufacturing a warp knit net, where said net comprises a plurality of net meshes (10), each of which is defined by a polygon with at least three sides (12) and as many knots (N) which connect a net mesh to adjacent meshes, each side being formed by a chain of loops comprising at least a first yarn (T1) and at least a second yarn (T3), comprising
- working said first yarn (T1) in such a way that it forms first yarn (T1) mutually interlaced turns so as to form a primary interlacement of the chain of loops; the method being characterized in that it further comprises:
- working said second yarn (T3) in such a way that it passes through said primary interlacement and that in at least one portion of the chain of loops before and immediately after the knots (N) of the warp knit net it forms second yarn (T3) mutually interlaced turns which are also interlaced with first yarn (T1) mutually interlaced turns of adjacent courses so as to form a reinforcing interlacement of the chain of loops.
Method according to the previous claim, wherein before or after said step of working said second yarn (T3) to form the reinforcing interlacement, said second yarn (T3) is worked in such a way as to form the core or filling of the primary interlacement.
Method according to claim 7 or 8, further comprising the step of working a third yarn (T2) in such a way that it forms the core or filling of the primary interlacement.
Warp knitting machine to manufacture a net according to any of the claims 1 to 6 comprising mechanical and/or electromechanical devices controllable in such a way as to implement the method for manufacturing a net according to any of the claims 7 to 9.