EP2800829B1

EP2800829B1 - Device for forming a fabric recessed selvedge on shuttleless looms

Info

Publication number: EP2800829B1
Application number: EP12791279.8A
Authority: EP
Inventors: Antonio Nicolini
Original assignee: Manea Textile Srl
Current assignee: Manea Textile Srl
Priority date: 2011-09-22
Filing date: 2012-09-21
Publication date: 2017-06-28
Anticipated expiration: 2032-09-21
Also published as: WO2013042158A3; EP2800829A2; ITVI20110255A1; WO2013042158A2

Description

The present invention relates to webbing and in particular it relates to a device for forming a fabric recessed selvedge for shuttleless looms.
More particularly, the invention concerns a selvedge device having a simple and compact structure so as to achieve lightness and stiffness features that are needed for the high working speed of the looms; specifically, the invention concerns a device which is exclusively constituted by mechanical components, particularly suitable for forming a recessed selvedge to the side edges of a fabric by using a method of folding the tails of the weft within the mouth formed by the warp yarns in a shuttleless loom.
It is well known that the side selvedges of shuttle looms cannot be obtained in shuttleless looms, because the weft thread is not continuous, but it is cut after each insertion. The fabric has, therefore, the side edges consisting of fringes of free wefts which may be partially interwoven with a certain number of additional warp yarns, forming the so-called "leno selvedges"; alternatively, when the quality or the features of the fabric require that the ends of the wefts are more firmly bound to the fabric, the above-mentioned method of folding the weft tails is used.
In particular, the side edges of the fabric are obtained by reinserting the weft tails into the shed soon after that the loom comb has beaten the weft, thereby forming the so-called "tucked or recessed selvedge"; therefore, it is not necessary to reinforce the fabric edges with mechanical systems for twisting and rotating additional warp yarns, which are not very reliable.
The selvedges re-entering process is normally carried out by means of known selvedge devices, which comprise means for gripping and cutting the weft yarn that is inserted in the warp passage; in practice, the operation of said selvedge devices is based on the fact that a needle is used to grasp the end of the cut weft thread, the so-called "pigtail", to make it fit, folded, into the warp shed, as soon as the latter is opened again for the next step, so as to be stretched again and beaten with the next weft, thus creating a recessed selvedge.
Selvedge devices of the above mentioned type are well known and are described, for example, in US3951177 , US4076049 , IT1251849 and IT1244762 .
In particular, the Italian patent IT 1244762 describes a mechanism for selecting the movement of the movable members of a device for forming a fabric recessed selvedge, which is constituted by a touch probe hinged at one end on the device's casing; the mechanism is cooperating, through a spring, with one of the cams actuating the control levers of the movable members, so as to cause an oscillation of a bridge small castle, integral with said mechanism, from a first to a second position.
In the first position, the bridge of the small castle interacts with the abutments of the actuating levers in order to block them in a fixed position, while in the second position there is no longer interaction and a metal anchor which is integral with the touch probe is supported by an electromagnetic device.
However, such a known selvedge device is rather complex and requires accurate adjustments; also, because of the remarkable overall dimensions of the yarn gripping and cutting means, it is necessary to cut into several parts the loom's beating comb, when the production of several fabrics on the same machine is required.
Furthermore, the known mechanical selvedge devices are suitable to work on looms operating at few revolutions per minute and, for this reason, they are not easily adaptable to the most recent looms, which are able to operate at a very high number of revolutions per minute, because the needle and the weft yarn gripping and cutting means are controlled by kinematic means that are very complex and bulky and therefore they cannot operate at the high speeds that are reached by the modern looms.
It is also known to use selvedge devices that employ pneumatic or mechanical-pneumatic recessed selvedge forming means, but, even in these cases, the technical solutions are rather unsatisfactory and unreliable and have serious technical drawbacks.
For example, the Italian patent IT 1251849 describes a device for forming a recessed selvedge in an air jet loom, comprising devices for inserting the weft yarn inside the shed, a comb to beat the yarn when inserted, and weft cutting means; the device also includes suction and cutting means, which are moved with independent cyclical movements, so that said means are switched from a first position to a second position and to a third position in the following way:

at the first position, the suction means are adjacent to the weft and to the comb and the cutting means are in a rest position and do not interfere with the comb when the latter is ready for beating,
at the second position, the cutting means are near the weft so as to cut the yarn and the suction means stay on the first position for sucking the free weft "pigtail", while
at the third position, the suction means are placed laterally to the open shed to insert herein the sucked "pigtail", which is expelled by means of a flow reversal action of the internal fluid, and the comb is far from the beating position.

Moreover, a device for forming a fabric recessed selvedge having the technical features of the preamble of the appended claim 1 is known for example from EP454238A1 . A selvedge forming device with pulleys, a toothed belt and a belt tensioner is known from JP200100342 .
The main object of the present invention is, therefore, to obviate the above mentioned drawbacks of the prior art, by making an improved device for forming a fabric recessed selvedge, that is entirely adaptable to the modern shuttleless looms.
Another object of the invention is to provide a device for forming a fabric recessed selvedge for shuttleless looms, which guarantees high precision and functional, mechanical and technological reliability, when the weft ends ("pigtails") go back into the warp mouth or shed.
Another object of the invention is to provide a device for forming a fabric recessed selvedge for shuttleless looms, which includes yarn processing units that are able to perform repeatable instantaneous movements.
A further object of the present invention is to provide a device for forming a fabric recessed selvedge for shuttleless looms, which has a simple and compact structure in order to achieve lightness and stiffness features that are needed for the higher working speeds of the modern looms.
Another object of the invention is to provide a device for forming a fabric recessed selvedge for shuttleless looms, which is able to minimize the length of weft ends, resulting in a narrow fabric recessed selvedge, and which is able to eliminate, at the same time, the need for a comb cutting when central recessed selvedges are provided.
These and other objects, which will become clear in the following, are obtained by making a device for forming a fabric recessed selvedge for shuttleless looms, according to the attached claim 1; additional technical features are mentioned in the dependent claims. Advantageously, the device for forming fabric recessed selvedges (selvedge device) according to the present invention allows to obtain a remarkable functional reliability when the weft ends re-enter the warp mouth; this is due to the accuracy and repeatability of the movements of the yarn processing units.
Furthermore, said device has a simple and compact structure, thereby achieving lightness and stiffness features that are needed for the high working speeds of the modern shuttleless looms; in particular, the size of the group including a leg and a shear, which are able to process the yarn, are extremely compact and suitable for minimizing the length of the re-entering weft ends, resulting in a suitably narrow fabric recessed selvedge.
Finally, the selvedge device according to the invention allows operation without interference with the group consisting of the leg and the shear and with the comb, when the comb is ready for beating, thus avoiding a comb cut when central recessed selvedges are provided and thus allowing to make horizontal adjustments of the leg-shear group and the hook group that are perpendicular to the fabric making line, depending on the "recovery" given by the elastic displacement of said fabric making line when the comb is ready for beating.
Further technical characteristics and advantages of the device for forming a fabric recessed selvedge in shuttleless looms, according to the present invention, will appear more clear from the following description that refers to preferred embodiments of the invention and from the attached drawings, in which:

figure 1 shows a perspective view of a first embodiment of the device for forming a fabric recessed selvedge in shuttleless looms, according to the present invention, in a first working position;
figure 2 shows the device of figure 1 without the outer casing;
figure 3 shows a partial exploded view of the device of figures 1 and 2, according to the present invention;
figure 4 shows a rear partial view of the device of figure 2, according to the present invention;
figure 5 shows an enlarged detail of figure 2, according to the present invention, in a first operating position;
figure 6 shows the same enlarged detail of figure 5, according to the invention, in a second operating position;
figure 7 shows a perspective view of a further embodiment of the device for forming a fabric recessed selvedge in shuttleless looms, according to the present invention, in a first operating position;
figure 8 shows the device according to figure 7, without the outer casing;
figure 9 shows a rear perspective view of the device of figure 8, according to the present invention;
figure 10 shows a perspective view of the device of figure 8, according to the present invention, in a second operating position.

Referring to the attached figures 1-6, the device 100 for forming fabric recessed selvedges according to the invention substantially comprises:

an external containment casing 1',
a leg-shear group 1, which is provided for grasping and cutting the tail of the weft yarn 2, which protrudes from the edge of the fabric 3,
a hook group 4 with a hook or needle 5, around which the weft yarn 2 is wrapped and then is dragged and folded towards the center of the fabric 3 between the warp yarns 6, which are arranged for a subsequent insertion of the weft yarn 2,
two parallel rods 7, 8 that are moved with reciprocating translational movements so as to control the movements of the leg-shear group 1,
a further rod 9, which is parallel to the rods 7, 8 of the leg-shear group 1 and which is moved with reciprocating translational and rotational movements so as to control the movements of the hook group 4.

Each rod 7, 8, 9 is secured to a respective gear 10, 11, 12, which is driven, in turn, during its linear translation motion, by a respective pair of conjugated cams 13, 14, 15, which act on the corresponding touch probes 13', 14', 15', while the rotary oscillation motion of the hook group 4 is controlled by a suitable pair of conjugated cams 16, which acts, through the touch probes 16', on a L-shaped lever 18, which, through a tie rod 19, is able to rotate the sleeve 20.
The rod 9 is able to slide longitudinally inside the sleeve 20; moreover, the rod 9, inside the sleeve 20, is shaped so as to control the rotation while allowing an axial sliding (as shown in detail in the attached figure 4), thus being able to control the rotation of the needle 5; in particular, said rod 9 can be shaped as a shackle member or can be replaced with generic grooved couplings.
The structure of the above mentioned mechanical control units is particularly simple and effective, as well as the movable units of the device according to the invention are rather light, easy to assemble and stiff, so as to guarantee precision and repeatability for handling the weft ends also at working high speeds of the looms.
The three conjugated cams 13, 14, 15 which drive the translation of the rods 7, 8, 9 and the conjugated cam 16 which drives the rotation of the rod 9 are all mounted on the drive shaft 21, driven by a toothed pulley 22, which is in turn connected, through a toothed belt 23 having a belt tensioner 24, to a second toothed pulley 25, mounted on the shaft 25', which protrudes from the gear casing able to take its motion from a command underlying the fabric 3.
The loosening of the belt tensioner 24 provided on the toothed belt 23 allows a longitudinal sliding, in a direction perpendicular to the comb 40, of the entire device 100 in an advanced or retracted position with respect to the support plate 1".
Therefore, it is possible to bring near or move away the leg-shear group 1 and hook group 4 from the fabric formation edge as a function of the characteristics and requirements of the same fabric 3.
Once the desired operation is carried out, the belt tensioner 24 is repositioned to restore the tension needed for a proper functioning of the toothed belt 23. With particular reference to the attached figures 5 and 6 and making reference to the functioning of the device for forming recessed selvedges, which is the object of the present invention, a "selvedge re-entering" cycle may be summarized as follows.
The leg-shear group 1 is maintained in a vertical position to receive the weft 2; in this position (shown in detail in the attached figure 5), the shear 27 is open and the grasping foot 28 is kept open and lowered by a suitable cam 29, which acts on the top of the stem 28' of the foot 28 and which is mounted on the rod 9 of the hook group 4, while the needle 5 is maintained in a raised position, outside the warp 6, by actuating the rod 9.
Then, once the weft yarn 2, after having beaten by the comb 40, has entered the foot 28, said foot 28 is closed with a partial rotation of the needle's 5 axis (as shown in detail in the attached figure 6). Furthermore, the two driving rods 7, 8 of the leg-shear group 1 may move and translate synchronously to push forward or backward the whole leg-shear group 1 or may translate at different distances so as to rotate the portion 33 of the group 1 around the pivoting pin 30 and to obtain the fabric weft cutting through the shear 27 and the winding of the weft yarn 2, held by the foot 28, around the needle 5.
Then, the hook or needle 5, actuated by the roto-translating motion of the driven rod 7, engages the weft yarn 2 and drags it inside the warp shed, where it is beaten by the comb 40 together with the weft which is inserted subsequently the weft yarn 2.
It should be noted in particular that the opening of the grasping foot 28, which is carried out by the hook group 4, takes place while the leg-shear group 1 is steady, that is to say without movements for opening or closing said group 1 (as instead realized in other known devices), thus minimizing the overall dimension of the leg-shear group 1 (as well as the functional spaces), so that when it devices for forming central recessed selvedges (such as the device shown in the attached figures 7-10), that are used when several fabrics are made with a same loom, are needed, it is not necessary to cut the comb 40 in the space between two adjacent fabrics, thus making more versatile the use of the combs.
Finally, the rotation of the leg-shear group 1 around the pin 30 is obtained by differentiating the displacements of the two rods 7, 8, so that the slide 31, connected to the rod 7, is able to push, through the connecting link-block 32, the upper portion 33 of the leg-shear group 1, thus making it rotate around the pivoting pin 30, which is placed in the lower portion 34 of the group 1 that is connected to the rod 8.
As already mentioned in the above, the attached figures 7-10 show respective views of a device 101 for forming fabric central recessed selvedges; the device 101 is made by introducing within a same casing 101', similar to the casing 1' of figure 1, two twin similar groups having the same functionality as that of the lateral group described above; in particular, in the attached figures 7-10, the elements having structural and functional characteristics that are similar or equal to the characteristics of the elements shown in the attached figures 6-10 are indicated with the same reference numbers.
Based on the foregoing, it is understandable how the device for forming a fabric recessed selvedge in shuttleless looms, which is the object of the present invention, achieves the intended aims and advantages previously mentioned.
In particular, the shape and dimensions of the device according to the invention allows to minimize the inevitable bending and/or vibrations of the leg-shear group, ensuring the repeatability of the movement and positions with respect to the yarn and/or to the weft end.
Furthermore, the action of the cam 29, which is applied to the hook axis and which, through the rotation of said axis, provides for opening the leg to house the weft yarn and for closing the leg to hold it in a following step when it is wounded around the hook without any movement of the leg-shear group, allows to reduce the size of said leg-shear group in a direction perpendicular to the comb, so as not to interfere with said comb when it is ready for beating; according to the prior art, in fact, the leg is usually opened by the reciprocal actions that take place between the different portions of the leg-shear group, which must also perform wide translations and rotations to carry out the yarn cutting and the yarn wrapping around the hook.
Finally, according to the invention, it is also possible to suitably adjust the device according to the compactness features of the fabric (with respect to the specific load factor of said fabric) and to the elastic displacement of the fabric making line when the comb is ready for beating.
The invention thus conceived is however susceptible of numerous modifications and variations, all falling within the scope of the claims; furthermore, all the details may furthermore be replaced with other technically equivalent elements.
Where the features and techniques mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly said reference signs do not have any limiting effect on the interpretation of each element identified, by way of example, by said reference signs.

Claims

Device (100, 101) for forming a fabric (3) recessed selvedge on shuttleless looms comprising substantially
- a taking and cutting group (1), consisting of at least one foot (28) and at least one cutter (27), which is held upright in order to take and cut to size at least one tail of a weft yarn (2) protruding from one edge of a fabric (3),

- at least one hooking group (4), which includes at least one hook or needle (5), said tail of the weft yarn (2) being wrapped around said hook or needle (5) and being dragged and folded toward the center of the fabric (3), between the warp yarns (6) arranged for the insertion of the weft tails (2),

- at least two first rods (7, 8), parallel to each other and moving according to an alternate translational motion, which are able to drive said taking and cutting group (1),

- at least one second rod (9), parallel to said first rods (7, 8) and moving according to a rotational or translational motion, which is able to drive said hooking group (4),
wherein each of said first (7, 8) and second (9) rods is linked to a respective carriage (10, 11, 12), driven in turn to linearly translate by means of at least one respective pair of first combined cams (13, 14, 15), which act on corresponding first probe means (13', 14', 15'), while said hooking group (4) is driven according to an oscillating rotary motion by means of at least one pair of second combined cams (16) acting, through second probe means (16'), on at least one lever (18), which drives in rotation at least one sleeve (20), said second rod (9) being longitudinally inserted into said sleeve (20),
wherein said first (13, 14, 15) and second combined cams (16) are mounted on at least one drive shaft (21), characterized in that said drive shaft (21) is driven by at least one first toothed pulley (22) of the device (100, 101), which is connected, via a toothed belt (23) equipped with a belt-tensioner (24) of the device (100, 101), with at least one second toothed pulley (25) of the device (100, 101), which is mounted on a shaft (25') coming out a gearbox able to take the motion from a command placed below said fabric (3), and characterized in that said belt-tensioner (24) is movable so as to allow sliding of said taking and cutting group (1) with respect to a support plate (1") of the device (100, 101).
Device (100, 101) as claimed in claim 1, characterized in that, internally to said sleeve (20), said second rod (9) is shaped so as to rotate and axially slide, said second rod (9) being also able to drive in rotation said hook or needle (5).
Device (100, 101) as claimed in at least one of the preceding claims, characterized in that means are provided to longitudinally slide said taking and cutting group (1) in a direction which is perpendicular to a comb (40) of the loom, so as to bring the taking and cutting group (1) near a fabric (3) formation edge or to send it away said fabric (3) formation edge.
Device (100, 101) as claimed in at least one of the preceding claims, characterized in that said foot (28) of the taking and cutting group (1) is driven by a relative cam (29), which acts on the top of a stem (28') of said foot (28) and which is mounted on said second rod (9) of the hooking group (4), said second rod (9) being able to drive said hook or needle (5) in a raised position outside the warp (6) of the fabric (3) or in a lowered position on said warp (6) of the fabric (3).
Device (100, 101) as claimed in at least one of the preceding claims, characterized in that said first rods (7, 8), which drive said taking and cutting group (1), are able to push forward or back said taking and cutting group (1) or shift by different lengths, so as to rotate at least one portion (33) of said taking and cutting group (1), in order to cut the fabric (3) weft (2) by means of said cutter (27) and to wrap said weft tail (2), which is retained by said foot (28) of said taking and cutting group (1), around said hook or needle (5), said hook or needle (5) being able to bring said weft tail (2) inside the warp mouth, where a comb (40) of the loom is provided for beaten the weft tail (2) together with the following weft.
Device (100, 101) according to claim 4, characterized by the fact that said hooking group (4) drives the opening of said foot (28) of the taking and cutting group (1), while said taking and cutting group (1) is stationary.