|
(11) | EP 1 624 096 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||
| (54) | DEVICE FOR WEAVING THE TRIMMINGS OF A FABRIC PRODUCED BY MEANS OF SHUTTLELESS WEAVING MACHINES |
| (57) A device for weaving the trimmings (23) of a fabric (24) produced by means of shuttleless
weaving machines, comprising a device (1) with at least one satellite epicycloid gearing
(13), each of which has at least one eyelet (8), situated in an eccentric position
with respect to the axis (6) of the relative satellite (13), following an elliptic
path; the weaving threads (4, 4A), passing through said eyelets (8), come from packs
(2) of yarn arranged on a support (9) outside the device (1), which can rotate in
synchrony with the gearing (11), so as not to intertwine the threads (4, 4A) with
each other in the feeding tract, or can remain fixed, when the gearing (11) is rotated,
alternately, in two opposite directions, so as to maintain the twist exerted or removed
from the threads (4, 4A) on an average null.
|
[0001] The present invention relates to a device for weaving the trimmings of a fabric produced by means of shuttleless weaving machines.
[0002] As is known, the weaving of the side trimmings of a fabric must be effected by interlacing the warp and weft threads so as to prevent the side warp threads from becoming unthreaded from the weft threads.
[0003] The most widely used weaving method, called slotted leno heald, consists in controlling the position of a pair of threads to form a so-called "warp mouth", similar to that of the other warp threads, by inverting the reciprocal position for each, or more, weft insertion(s).
[0005] A first type of traditional device uses, in particular, a disk with two holes through which the weaving threads pass, wherein the disk is placed parallel to the threads in order to effect the weaving.
[0006] This device, however, has the drawback of vertical encumbrance, which prevents the device itself from being housed inside the doup-heald frame, thus limiting the maximum number of installable frames.
[0007] A further disadvantage lies in the fact that as the disk holes run in a circular path, they scrape the weaving threads with the consequent risk of damage due to wear.
[0008] Other types of devices are proposed for solving the problem of vertical encumbrance and can be positioned inside the doup-heald frames, but still have drawbacks, among which the possibility of causing excessive sliding between the guiding eyelets and the threads and/or excessive transversal encumbrance, which limits the maximum weaving height of the machine.
[0009] The most commonly used devices for weaving the trimmings of a fabric are called "rotating splitz" and are based on an epicycloid gearing having the reserves of the two weaving threads installed on board.
[0010] These devices represent a good compromise from the point of view of controlling the opening angle of the weaving threads (which, in practice, follows a sinusoidal law, if a constant rotation rate of the gearing is imposed) and of the path (of the elliptical type) of the guiding eyelets of the threads.
[0011] This type of device, however, has the problem of encumbrance, due to the fact that the thread feeding spools are assembled on the satellites of the epicycloid gearing of the device itself.
[0012] This means that it is practically impossible to position the device inside the doup-heald frame, due to the encumbrance and this fact also limits the dimensions of the packs of yarn which feed the weaving threads.
[0013] An objective of the present invention is to overcome the above drawbacks and, in particular, to provide a device for weaving the trimmings of a fabric produced by weaving machines, which reduces the overall encumbrance of the system, regardless of the dimensions of the yarn packs used, which are situated outside the device itself.
[0014] Another objective of the invention is to provide a device for weaving the trimmings of a fabric produced by weaving machines, which allows the efficient control of the thread opening, so as to obtain the same opening angle of the upper and lower thread, thus nullify-ing/minimizing the sliding between the threads in the feeding tract between the yarn packs and the device itself.
[0015] A further objective of the invention is to provide a device for weaving the trimmings of a fabric produced by weaving machines, which allows the percentage elongation of the threads in the shed opening to be reduced.
[0016] An additional objective of the invention is to provide a device for weaving the trimmings of a fabric in a simple, fast, precise, economical and reliable way.
[0017] These objectives are achieved by producing a device for weaving the trimmings of a fabric produced by means of weaving machines according to claim 1.
[0019] Advantageously, the present invention retains the technical properties of the epicycloid gearings ("rotating splitz") of the known type, it overcomes encumbrance problems and, with respect to all the traditional systems, reduces the percentage elongation of the threads, in the shed opening.
[0020] Further characteristics and advantages of a device for weaving the trimmings of a fabric produced by means of weaving machines will appear more evident from the following description and enclosed figures, which are provided for illustrative and non-limiting purposes, in which:
- figure 1 shows a complete perspective view of the device for weaving the trimmings, object of the present invention;
- figure 2 is a perspective view illustrating the thread feeding side of the device shown in figure 1;
- figure 3 is a sectional view of the device of figure 1, taken along the line III-III of figure 1;
- figure 4 shows a Cartesian diagram of the trend of the opening angle of the thread near the selvedge weaving in relation to the rotation angle of the gearing of figure 1.
[0021] With particular reference to figures 1-3, 1 generically indicates a device with an epicycloid gearing of the known type, comprising, inside a shaped support 10, a circular plate 11, made to rotate by known means, along the direction of the arrow F in figure 1, so as to distribute the rotatory movement to two satellites 13, each of which is connected to the relative weaving thread 4, 4A.
[0022] In particular (fig. 2), the yarns 4, 4A, arranged in pairs, are guided into the device 1 through the duct 14 of the supporting element 15 and from there to the centre of the plate 11, inside the shaped hole 16.
[0023] The weaving threads 4, 4A are then split and passed through the central openings 17, 18 (fig. 1) of the satellites 13 and subsequently deviated inside the eyelets 8, in turn assembled on suitable brackets 19, 20, until they converge in correspondence with the path 21, which represents the weaving points 22 of the selvedge 23 of the fabric produced, the latter generically marked with 24.
[0024] Both the eyelets 8 are positioned eccentrically with respect to the relevant axis 6 (fig. 3) of each satellite 13, so that the above eyelets 8 follow elliptical paths.
[0025] In any case, the passage through the eyelets 8, positioned eccentrically on the satellites 13, is known art, as is also the weaving procedure.
[0026] According to the present invention, the spools, marked with 2 in figure 1, of the weaving threads 4 and 4A, are positioned on an external support 9, rotating along the direction of the arrow G of figure 1, and the threads 4 and 4A enter the epicycloid device 1, first at the center of the plate 11, near the revolution axis 5 of the satellites 13, and then to the centre of the respective satellites 13, close to the relative rotation axes 6.
[0027] The device can operate according to two different modes and, in particular, with the support 9 in synchronous rotation with the rotating plate 11, when the latter rotates in a single direction, in order to avoid an accumulation of the intertwining of the threads 4, 4A with each other, in the tract between the interception 3 and the device 1, or with the support 9 fixed, when the rotating plate 11 is rotated alternately for a certain number of rounds in the two opposite directions, maintaining the intertwining of the weaving threads 4, 4A in the tract existing between the interception 3 and the device 1, on an average null.
[0028] The reduction in the elongation of the threads 4, 4A is due to the fact that the "splitz" with epicycloid gearings, such as that used in the present invention, does not also form a shed at the thread feeding side and distributes the elongation caused by the anterior warp shed (in correspondence with the formation side of the fabric 24) on a thread length extended to the packs 2 of yarn.
[0029] Finally, the device described is capable of maintaining the opening angles of the yarn, marked by α and β in figure 1, almost equal in all phases, by optimising the opening of the weaving threads 4, 4A and minimizing the respective sliding of the threads 4, 4A in the feeding zone, particularly in the operating mode with a fixed support 9 of the yarn packs 2.
[0030] In this case, unlike the known devices which have a delayed or anticipated opening angle of the thread with respect to a comparative sinusoidal law, depending on whether the thread is opened in the upper or lower part, (i.e. the angle α is different from the angle β in many of the operating phases of the device), as shown in the diagram of figure 4, the use of the device according to the invention causes a trend of the thread opening angle in the upper part (angle α) and in the lower part (angle β) which practically follows a sinusoidal law, if a constant rotation rate of the rotating plate 11 is established.
[0031] From the above description the characteristics of the device for weaving the trimmings of a fabric produced by weaving machines, which is the objective of the present invention, are evident, as are also the relevant advantages.
[0032] In particular they refer to the following aspects:
- reduction in the vertical and transversal encumbrance, also maintaining a sufficient opening angle of the weaving threads;
- minimum phenomena of sliding and of general damage to the weaving threads;
- efficient control of the opening angle of the weaving threads and of the path (of the elliptical type) of the guiding eyelets of the threads themselves.
[0033] Finally, numerous other variations can obviously be applied to the device in question, all included in the novelty principles of the inventive idea. It is also evident that in the practical embodiment of the invention, the materials, forms and dimensions of the details illustrated can vary according to the demands and can be substituted by other technically equivalent alternatives.
1. A device for weaving the trimmings (23) of a fabric (24) produced by weaving machines,
comprising a device (1) with at least one satellite epicycloid gearing (13), suitable
for distributing two weaving threads (4, 4A) in correspondence with the points (22)
of the fabric (24) where the weaving of the trimmings (23) is to be effected, characterized in that said weaving threads (4, 4A), connected to said respective satellites (13), come
from packs of yarn (2) arranged on at least one support (9) outside the device (1).
2. The device according to claim 1, characterized in that said support (9) of the yarn packs (2) rotates (G) in synchrony with said epicycloid
gearing, to prevent the intertwining of the weaving threads (4, 4A) with each other,
in the feeding tract.
3. The device according to claim 1, characterized in that said support (9) of the yarn packs (2) is fixed and said epicycloid gearing is rotated
(F) alternately in the two directions, with programmable sequences, so as to maintain
the twist exerted or released from the weaving threads (4, 4A), on an average null.
4. The device according to claim 1, characterized in that said epicycloid gearing comprises, inside a shaped support (10), a rotating (F) circular
plate or disk (11), suitable for distributing the rotational movement to two satellites
(13), said weaving threads (4, 4A) being arranged in pairs in the feeding tract and
being guided into the device (1) in correspondence with said plate or disk (11).
5. The device according to claim 4, characterized in that said weaving threads (4, 4A) are decoupled downstream of said plate or disk (11)
and are deviated inside respective eyelets (8) present on each satellite (13), until
they converge in correspondence with a path (21), which represents all the weaving
points (22) of the selvedge (23) of the fabric (24).
6. The device according to claim 5, characterized in that said eyelets (8) are positioned eccentrically with respect to the relative axis (6)
of each satellite (13), so that said eyelets (8) follow an elliptic path.
7. The device according to claim 4, characterized in that said weaving threads (4, 4A) are guided into the device (1), close to the revolution
axis (5) of said satellites (13), and are then guided centrally, near the rotation
axis (6) of said satellites (13).
8. The device according to claim 1, characterized in that said device (1) maintains the opening angles of the yarn (α, β), substantially equal
in all phases, optimizing the opening of the weaving threads (4, 4A) and nullifying
the relative sliding between the threads (4, 4A) in the areas where they can be intertwined.