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Title:
DEVICE FOR OPENING A GRIPPING ELEMENT OF WEFT YARN OF A GRIPPER LOOM, RELATED GRIPPING ELEMENT AND METHOD FOR OPENING SUCH GRIPPING ELEMENT
Document Type and Number:
WIPO Patent Application WO/2017/081712
Kind Code:
A2
Abstract:
A device (10, 100) is described, for opening a gripping element (1010, 1100) of weft yarn of a gripper loom, comprising opening means (11, 101) and positioning means (12, 102), moving between two different operating positions, a drive (20) adapted to control the motion of the opening means (11, 101) and of the positioning means (12, 102). A gripping element (1010, 1100) of weft yarn of a gripper loom actuated by such device (10, 100) is further described. A method for opening such gripping element (1010, 1100) of weft yarn is further described.

Inventors:
PEZZOLI, Luigi (Via Ciro Menotti 5, Gandino, I-24024, IT)
PEZZOLI, Nello (Via Ciro Menotti 5, Gandino, I-24024, IT)
Application Number:
IT2016/000264
Publication Date:
May 18, 2017
Filing Date:
November 10, 2016
Export Citation:
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Assignee:
P.T.M.T. S.R.L. (Via Ciro Menotti 5, Gandino, 1-24024, IT)
International Classes:
D03D47/20; D03D47/23
Domestic Patent References:
WO1997040218A11997-10-30
WO2011018062A12011-02-17
Foreign References:
EP2462267B12013-09-11
Attorney, Agent or Firm:
GARAVELLI, Paolo (Garavelli Paolo, A.bre.mar. S.R.L.VIa Servais 27, TORINO, 1-10146, IT)
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Claims:
CLAIMS

Gripping element (1010, 1100) of weft yarn of a gripper loom comprising a device (10, 100) for opening said gripping element (1010, 1100), said device (10, 100) comprising opening means (11, 101) and positioning means (12, 102) of the weft yarn, moving between at least two different operating positions, in a plane containing a direction line of said gripping element (1010, 1100), a drive (20) which controls the motion of said opening means (11, 101) and said positioning means (12, 102), through a linkage (21, 22), the motion of said opening means (11, 101) and said positioning means (12, 102) occurring along the same motion direction of said gripping element (1010, 1100) of weft yarn, said opening means (11, 101) and said positioning means (12, 102) not interacting with the warp yarn, said opening means (11, 101) comprising a punch and said positioning means (12, 102) comprising an appendix belonging to a runner (23) connected to said linkage (21, 22), said runner (23) sliding along a guide (24) along the same motion direction of said gripping element (1010, 1100) of weft yarn, characterized in that it comprises at least one gripper with a front opening adapted to receive at least the punch belonging to said opening means (11, 101), between a main body

(1011, 1101) and a cover (1012, 1102), said main body (1011, 1101) interacting with said cover

(1012, 1102) through elastic elements (1013, 1103, 1104).

Gripping element (1100) according to the previous claim, characterized in that the appendix belonging to said positioning means

(102) is equipped with a positioning profile having substantially a central hollow zone which allows the weft yarn to freely slide.

Gripping element (1100) according to the previous claim, characterized in that said main body (1101) and said cover (1102) extend on their fronts towards the fabric.

Gripping element (1100) according to the previous claim, characterized in that said elastic elements (1104) are composed of a series of leaf springs arranged as a fan comprising at least one leaf spring slanted with respect to an insertion direction to allow distributing the load on many points. Method for opening a gripping element (1010) of weft yarn according to claim 1, characterized in that it comprises the following steps:

a) a hook (1014) of the gripping element (1010) overcomes the weft remaining substantially in a lowered position while the gripping element (1010) is next to its reversal;

b) the runner (23) moves with an opposite motion starting to lift the cover (1012) ;

c) the weft is kept in position by the appendix (12) towards the supplying assembly of the weft and is fastened to the fabric with its other end;

d) upon inverting the gripping element (1010) the runner (23) continues for a short section to follow the gripping element (1010), allowing a perfect insertion of the weft in the holding area;

e) the runner (23) reaches its reversal while the gripping element (1010) continues with its return movement;

f) the two movements, by being combined, perform the closure of the cover (1012), performing the gripping;

g) in its return movement, the gripping element (1010) reaches and overcomes the cutting device which, by cutting the weft from the fabric, allows reaching the opposite end.

6. Method for opening a gripping element (1100) of weft yarn according to any one of claims 1 to 4, characterized in that it comprises the following steps :

a) the gripping element (1100), having reached the end of the fabric, interacts with the opening punch (101) , while the weft is kept in position by the brake of weft (32);

b) the alredy cut weft is kept in a preset position by the positioning profile (102) , very near the end of the fabric;

c) cutting is performed when the gripping element (1100), having reached the opposite end of the fabric, disengages the weft;

d) the punch (101) will place the positioning profile (102) inside the body of the gripping element (1100) , till the weft, which is always unmoving, will be overcome by the gripping element (1100) ;

e) upon reverting the motion of the gripping element (1100) , the punch (101) with the positioning profile (102), by sliding on the weft, extremely accurately positions this latter one next to the gripping element (1100) ;

f) the weft remains blocked or braked by the (32) till the gripping element (1100) is closed, and then, being gripped, will start moving, dragged by the gripping element (1100) ;

g) simultaneously, the brake (32) frees the weft by letting it slide.

Description:
DEVICE FOR OPENING A GRIPPING ELEMENT OF WEFT YARN

OF A GRIPPER LOOM, RELATED GRIPPING ELEMENT AND METHOD FOR OPENING SUCH GRIPPING ELEMENT

The present invention refers to a device for opening a gripping element of weft yarn of a gripper loom, a related gripping element and a method for opening such gripping element.

In particular, the present invention refers to a version of weaving looms eguipped with a single gripper which, by moving for the whole width of the fabric, reaches the opposite end, grips the weft and drags it to the other end. These looms are usually defined as mono-grippers .

The means of transport of the gripper can indifferently be flexible belts or rigid rods.

Weaving of particular wefts is more and more requested, such as to require a unilateral inserting system, a driven gripper, a mono-gripper . Such gripper inserted on a side of the fabric reaches the opposite end, pushed by a flexible belt or by a rigid rod. After having reached the end, the gripper grips the weft, reverses its motion for travelling back on the section in an opposite direction. After having reached the opposite end to the gripping, a pitch closure and an abutment end the weaving cycle, creating the fabric weaving.

Particularly important is the activity of gripping the weft, above all in case of particular yarns .

There are two types of gripping, negative and positive .

Negative gripping: the gripper equipped with wedge means hooks the yard adapted to slide to be inserted; no part of the gripper is moved to grip the yarn. It is a simple system, which allows high speeds. However, such system lacks efficiency and reliability in case of particular yarns, straps, multiple yarns, irregular yarns, delicate yarns.

Positive gripping: the gripper is opened and closed with suitable means through defined motion laws. The yarn enters the gripper with a substantially free path, because part of this is moved for creating room for entering the yarn and grip it. It is clear that this type of gripping is not heavily affected by the physical characteristics of the yarn, being able to use a controlled opening and closing of the gripper itself. Obviously, this system requires a more complex and heavier gripper structure, in addition to actuating means which interact with the warp yarn. The interaction of the actuating means for the gripper with the warp yarn is translated into a pressure onto the mobile part of the gripper, with the danger of creating undesired effects, such as the surface damaging of the warp yarn.

The most relevant prior art related to weft gripping activities, above all in case of particular yarns, is given by WO1997040218A1.

Patent document WO2011018062A1 discloses a gripper of a textile machine comprising a blocking device for a ribbon-shaped weft material adapted to be inserted in the pitch of a textile loom. The blocking device comprises a fixed gripping element and a spring-loaded gripping element, moving around a rotation axis and adapted to be actuated by control means to be able to open the blocking device, each gripping element having a blocking surface. The gripper comprises a loom, wherein the blocking surfaces are arranged substantially outside the loom.

Patent EP2462267B1 discloses a device for inserting a weft yarn, preferably shaped as a ribbon, comprising a supplying assembly for a gripping element of a mechanical loom with a blocking device for blocking a free end of the weft yarn, wherein the blocking device is substantially moving along the moving direction of the gripping element, between at least two different operating positions. The device for inserting a weft yarn comprises a drive for moving the blocking device, wherein the blocking device can be moved by means of a linkage comprising at least one rotatable arm adapted to be actuated by the motor. The drive is independent, while the linkage comprises two parallel rotating arms connected through a coupling element, wherein the blocking device is arranged next to the coupling element.

Object of the present invention is solving the above prior art problems, by providing a solution to opening the gripping elements which is capable of not damaging the warp yarn.

A further object is opening such gripping elements according to a rigorous motion law capable of guaranteeing the gripping of particular weft such as ribbons and straps.

The above and other objects and advantages of the invention, as will result from the following description, are obtained with a device for opening a gripping element of weft yarn of a gripper loom, between a supplying assembly and such gripping element, as claimed in claim 1.

The above and other objects and advantages of the invention, as will result from the following description, are further obtained with a gripping element of weft yarn of a gripper loom, and with a method for opening such gripping element of weft yarn, as claimed in their respective independent claims .

Preferred embodiments and non-trivial variations of the present invention are the subject matter of the dependent claims.

It is intended that all enclosed claims are an integral part of the present description.

It will be immediately obvious that numerous variations and modifications (for example related to shape, sizes, arrangements and parts with equivalent functionality) can be made to what is described, without departing from the scope of the invention as appears form the enclosed claims.

The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed drawings, in which:

- Figure 1 shows a front view of a first embodiment of the device for opening a gripping element of weft yarn of a gripper loom, according to the present invention;

- Figure 2 shows a front axonometric view of the device of the previous figure;

- Figure 3 shows a front view on the rear of the device of the previous figure;

- Figure 4 shows a read axonometric view of the device of the previous figure;

- Figure 5 shows a front view of a second embodiment of the device for opening a gripping element of weft yarn of a gripper loom, according to the present invention;

- Figure 6 shows a front axonometric view of the device of the previous figure;

- Figure 7 shows a front view on the rear of the device of the previous figure;

- Figure 8 shows a rear axonometric view of the device of the previous figure;

Figures 9, 10, 11 show orthogonally projected views of a first embodiment of the gripping element of weft yarn of a gripper loom, according to the present invention;

- Figure 12 shows a front axonometric view of the gripping element of the previous figure;

- Figure 13 shows a plan view of the assembly formed by the gripping element of the previous figure interacting with the device of Figures 1 to 4;

Figures 14, 15, 16 show orthogonally projected views of a second embodiment of the gripping element of weft yarn of a gripper loom, according to the present invention;

- Figure 17 shows a front axonometric view of the gripping element of the previous figure; and

- Figure 18 shows a plant view of the assembly formed by the gripping element of the previous figure interacting with the device of Figures 5 to 8.

With reference to the Figures, it is possible to note that a device 10, 100 for opening a gripping element 1010, 1100 of weft yarn of a gripper loom, between a supplying assembley and the gripping element 1010, 1100 comprises opening means 11, 101 and positioning means 12, 102, moving between at least two different operating positions, in a plane containing a direction line of the gripping element 1010, 1100, a drive 20 adapted to control the motion of the opening means 11, 101 and of the positioning means 12, 102, through a linkage 21, 22.

Advantageously, the motion of the opening means 11, 101 and of the positioning means 12, 102 occurs in the same motion direction of the gripping element 1010, 1100 of weft yarn. In particular, the opening means 11, 101 and the positioning means 12, 102 do not interact with the warp yarn.

When opening, the gripping element 1010, 1100 does not interact with the warp yarn.

With reference to Figures 1 to 8, in particular, the opening means 11, 101 comprise a punch, while the positioning means 12, 102 comprise an appendix.

Both the punch and the appendix belong to a runner 23 connected to the linkage 21, 22. In particular, the runner 23 slides along a guide 24 in the same motion direction of the gripping element 1010, 1100 of weft yarn.

With reference to Figures 5 to 8, a second configuration given by the device 100 comprises blocking means 30 adapted to keep the weft yarn blocked in a preset position. Preferably, the blocking means 30 comprise a drive 31 adapted to control a brake of the weft 32.

The appendix belonging to the positioning means 102 is equipped with a positioning profile having substantially a central hollow zone adapted to allow the weft yarn to freely slide.

With reference to Figures 9 to 18, the gripping element 1010, 1100 of weft yarn of a gripper loom actuated by the device 10 comprises at least one gripper with a front opening adapted to receive at least the punch belonging to the opening means 11, 101. Such front opening is formed between a main body 1011, 1101 and a cover 1012, 1102. Moreover, the main body 1011, 1101 interacts with the cover 1012, 1102 through elastic elements 1013, 1103, 1104.

With reference to Figures 14 to 18, in a second configuration given by the gripping element 1100 of weft yarn actuated by the device 100, the main body 1101 and the cover 1102 are frontly extended towards the fabric.

In particular, the elastic elements 1104 are composed of a series of leaf springs arranged as a fan, comprising at least one leaf spring slanted with respect to the insertion direction to allow distributing the load in many points. The arrangement of these leaf springs as afan is useful to guarantee a more uniform and efficient gripping, in order to embrace as much as possible the operating range of the elastic elements.

With reference to Figure 13, a method for opening the gripping element 1010 of weft yarn actuated by the device 10 comprises the following steps :

a) a hook 1014 belonging to the gripping element 1010 overcomes the weft remaining substantially in a lowered position while the gripping element 1010 is next to its reversal;

b) the runner 23 moves with an opposite motion starting to lift the cover 1012;

c) the weft is kept in position by the appendix 12 towards the reel and is fastened to the fabric with its other end;

d) upon reversing the gripping element 1010, the runner 23 continues for a short section to follow the gripping element 1010, allowing a perfect insertion of the weft in the holding area; e) the runner 23 reaches its reversal while the gripping element 1010 continues with its return movement ; f) the two movements, by being combined, perform the closure of the cover 1012, performing the gripping;

g) in its return movement, the gripping element 1010 reaches and overcomes the cutting device which, by cutting the weft from the fabric, allows reaching the opposite end.

With reference to Figure 18, a method for opening the gripping element 1100 of weft yarn actuated by the device 100 comprises the following steps :

a) the gripping element 1100, having reached the end of the fabric, interacts with the opening punch 101, while the weft is kept in position by the brake of weft 32;

b) the alredy cut weft is kept in a preset position by the positioning profile 102, very near the end of the fabric;

c) cutting is performed when the gripping element 1100, having reached the opposite end of the fabric, disengages the weft;

d) the punch 101 will place the positioning profile 102 inside the body of the gripping element 1100, till the weft, which is always unmoving, will be overcome by the gripping element 1100; e) upon reverting the motion of the gripping element 1100, the punch 101 with the positioning profile 102, by sliding on the weft, extremely accurately positions this latter one next to the gripping element 1100;

f) the weft remains blocked or braked by the 32 till the gripping element 1100 is closed, and then, being gripped, will start moving, dragged by the gripping element 1100;

g) simultaneously, the brake 32 frees the weft by letting it slide.

The device for opening a gripping element of weft yarn of a gripper loom of the present invention allows obtaining its stated objects.

The device allows positioning the weft, opening and closing in a controlled and positive way the gripper without having interactions with the warp yarn of the loom.

The invention deals with an innovative opening and closing system and its corresponding positive gripper to obtain the function of a positive gripping adapted to operare with particular wefts, solving the above described negative aspects. The advantages introduced by such system are:

- no contact with the warp threads, though remaining an important part of the gripper, including the elastic means, inside the pitch;

- by inserting itself inside the gripper, it does not exert any pressure outside the gripper opener/gripper system; in other words, during the gripping step, it does not press the same on external surfaces, removing the risk of signs on the warp;

being motored, it can characterize the gripping operation for every type of weft according to the arrangement for executing and inserting many types of weft.

The components of the device are: the opening punch equipped with a positioning profile for the weft and shaped in its front part with a pyramid profile towards the sliding direction of the gripper; the punch, sliding in a guide parallel to the sliding direction of the gripper and preferably actuated by a motor controlled through a linkage or directly through a motor of the linear type; a gripper composed of a main body and of a cover made in such a way that the front part of the assembly allows entering the punch. The tapered punch, the motion law of the gripper, and the motion law of the motor completely define the gripping mode. The motor, through an adjustment of the motion law, makes the gripping singular for every type of weft provided by the design of the fabric being executed. The main body houses the elastic elements which interact with the cover.

The device has two executions. The first one provides for the front part of the cover equipped with an open hook towards the opposite end of the fabric. The seconda one has an arrangement adapted for particularly wide wefts, better identified as ribbons, and provides for a front part of the gripper body and of the cover extended towards the fabric. The punch is equipped with a positioning profile having substantially a central hollow zone whose sizes are adequate to the weft to be woven. The weft must be able to easily slide within this recess .

As regard the gripper for wefts of the strap type, a front gripping, the arrangement of the elastic elements is very particular. Normally, the elastic elements lay in planes parallel to the sliding direction of the weft. In this case, in order to guarantee a good hold on the whole gripping front, a leaf spring has been added, which is slanted with respect to the insertion direction. This particular is very important, since it allows using materials for the gripper parts which are different from metals, like the most suitable composites for possible skidding with adjacent parts made of metal.

This because, by distributing the load in many points, the interaction between the holding elements (small plaques made of hard metal or equivalent) is more homogeneous, thereby guaranteeing a more uniform gripping of the burrs (filaments) or a better hold in case of very thin yarn thicknesses. The novelty consists in that there are many elastic elements arranged not along the same direction, but as a fan, in order to embrace as much as possible the operating range of the elastic elements.