EP1783254A1

EP1783254A1 - Warp yarn weaving device for selvedge formation in weaving looms

Info

Publication number: EP1783254A1
Application number: EP05425774A
Authority: EP
Inventors: Angelo Gallizioli; Dario Magoni
Original assignee: Promatech SpA
Current assignee: Promatech SpA
Priority date: 2005-11-04
Filing date: 2005-11-04
Publication date: 2007-05-09
Anticipated expiration: 2025-11-04
Also published as: ATE462030T1; DE602005020150D1; EP1783254B1; CN1958898A

Abstract

Warp yarn weaving device in a weaving loom, for selvedge formation or for leno heald weave at a cloth edge, wherein two small heald assemblies (1), integral with respective mutually parallel posts (2) having alternate and symmetrical rectilinear movement, control the position of two corresponding assemblies of said warp yarns. The motion is imparted to said posts (2) by an electric motor (3) having alternate rotational motions and apt to directly control in an alternate and symmetrical rectilinear motion a pair of driving rods (4) which are parallel to the posts (2) and connected thereto with no longitudinal play.

Description

The present invention refers to a warp yarn weaving device for selvedge formation in the manufacturing of cloths in weaving looms. In particular, the invention refers to a device of this kind equipped with a drive of its own which is independent from the loom main motor.
Dedicated devices, for the binding of warp yarns for selvedge formation, and for the possible formation therein of the so-called "heald weave" (leno devices), have been in use for a number of years and are well-known to experts in the field for their practicality. These are, in short, devices mounted on the loom, in the area between the reed and the heald frames meant for cloth formation, which act on specific warp yarn assemblies arranged on each cloth edge. The individual yarns of such warp yarn assemblies run through the eye of corresponding smaller healds, divided into two series which are alternately shifted into opposite directions - in a fully similar way to what happens with the heald frames for cloth formation - thereby allowing warp yarns to interweave with weft yarns, according to a specific selvedge weave which is independent from that of the main cloth. Some of such warp yarns can further be interwoven also horizontally, alternately in one direction and in the opposite one in one or more successive picks (in the leno heald weave), becoming twisted on the weft yarns in order to thereby obtain a tighter binding of the same, particularly in the selvedge outer area. The selvedge obtained through these devices in fact is also called "tied" selvedge and withstands fraying better than ordinary selvedges or - the strength thereof being similar - it may consist of a smaller number of warp yarns, thereby allowing reduced false selvedge waste.
A warp yarn weaving device for selvedge formation which represents the prior art of reference of the present invention is for example the one described in EP-A-393.467 , the essential elements of which are reported as figs. 1 and 2 in the accompanying drawings. In such patent it is in fact effectively suggested to accomplish the opening/closing movement of the warp yarns for selvedge formation through small heald assemblies (L1, L2) which are independent from the system of heald frames (Q) intended for cloth formation and controlled by a system of flexible stays (T1, T2) connected to the main motion of the loom by a single rope (F). The small healds of each assembly (L1, L2) are mounted on shelf arms (B) integral with two posts (M) having alternate rectilinear motion.
For the purpose of making the alternate motion of said posts (M), and consequently the one of the small healds (L1, L2), perfectly regular, symmetrical and with no play - keeping into account that the flexible stays (T1, T2) of course operate exclusively by traction and hence only in the lifting step of their respective posts (M) - said posts (M) extend above into rectilinear racks (C) integral therewith, cooperating with each other through an idle toothed wheel (R) pivoting about a support fixed to the loom. During the lifting movement of a post (M1) and of the small healds (L1) fixed thereto, the toothed wheel (R) hence determines a corresponding lowering of the other post (M2) and of the smaller heald assembly (L2) fixed thereto, thereby effecting the opening and closing movement of the warp yarns running through the central eyes formed in the small healds (L1, L2).
Although the known art device described above accomplishes very effectively the purpose for which it has been arranged, it requires the preparation of a system of stays consisting of a main rope F, moved with alternate motion by the loom central drive through a specific cam leverage with a return spring, and by secondary ropes T and corresponding transmission pulleys P for driving the small heald assemblies L. Although such device can in fact be manufactured in a very compact shape, it nevertheless has a certain bulk on the loom and always requires a certain amount of labour - whenever the position for selvedge forming is to be altered on the loom width - to detach and reattach stays T from main rope F and for the correct tensioning thereof.
Moreover, although the control of the small heald assemblies for selvedge formation can be achieved independently from that of the weaving machine controlling heald frames, it still depends on the loom central movement and any alteration thereof hence necessarily calls for the mechanical replacement of the cam effecting the transformation of the loom circular motion into the alternate motion of rope F.
It is hence an object of the present invention to provide a warp yarn weaving device for selvedge formation, in a weaving loom of the type described above, which allows to obtain all the advantages of the system of the known art, however removing therefrom the drawbacks mentioned above and, specifically, simplifying as much as possible the structure of the device and of the corresponding drive system and further allowing such drive to be changed quickly and with no mechanical actions.
According to the present invention, such object is achieved through a warp yarn weaving device having the features detailed in the accompanying main claim. Additional features of the invention are detailed in the dependent claims.
Further features and advantages of the device according to the present invention will in any case be clearer from the following detailed description of some preferred embodiments of the same, illustrated with reference to the accompanying drawings, wherein:

fig. 1 (prior art) is a front view of a selvedge binding device of the prior art;
fig. 2 (prior art) is a side view of the device of fig. 1, shown in its arrangement in connection with the other main weaving members of the loom;
fig. 3A is a perspective view of a first embodiment of the device according to the present invention;
fig. 3B is a front view of the device of fig. 3A;
fig. 4A is a perspective view of a second embodiment of the device according to the present invention;
fig. 4B is a front view of the device of fig. 4A from which, to allow improved understanding of the invention, the motor and the corresponding support structure have been removed; and
fig. 5A is a perspective detailed view which shows the detail of the double-grooved pulley of fig. 4B and of the corresponding control ropes;
fig. 5B is a perspective detailed view of the opposite side of the pulley of fig. 5A which houses the fixing area of the control ropes (not shown);
fig. 5C is a side elevation view of the side of the pulley visible in fig. 5B; and
fig. 5D is a section view according to line D-D of fig. 5C.

A first embodiment of the present invention is shown in fig. 3. The selvedge-forming device according to the invention has a general operative structure fully similar to the one described above with reference to patent EP-393.467 , except for what concerns the device operation means. As a matter of fact, it comprises two small heald assemblies (L1, L2) mounted on shelf arms (B) integral with two posts (M) having alternate rectilinear motion due to the fact that said posts (M) extend above into rectilinear racks (C) integral therewith, cooperating with each other through a toothed wheel (not visible in figs. 3).
As an alternative to the system of flexible stays provided in the prior art to operate the two small heald assemblies (L1 L2), according to the first embodiment of the present invention the operation of the posts (M), and consequently of the above-mentioned small heald assemblies, is accomplished by an electric motor 1 fixed to the support base S of the device. The support base S is each time securely and quickly fixed in the desired position along a suitable loom crossbar, by means of shelves T projecting from the same, using fixing means well-known per se. The drive shaft of motor 1 is directly keyed onto the axis of the toothed wheel which engages with the posts (M); said toothed wheel hence, unlike prior art disclosures, is not an idle wheel, but a motor wheel apt to control directly - through alternate rotations of electric motor 1 by which it is driven - the alternate rectilinear movement of the posts (M).
Motor 1 is connected in an electrical axis with the main motor operating the loom, so as to have the same operation frequency thereof, but the law of motion thereof, the degree of advance/delay of each individual cycle and the width of the corresponding stroke can instead be adjusted at will, even in a different way for each individual device - among multiple devices mounted on the same loom - through a simple software control which implies no mechanical action on the device nor, even less so, on the loom. The information required for such adjustment are supplied, in a manner known per se, by position sensors, Hall-effect sensors or other similar sensors according to the type of control which it is intended to give to the device.
Thanks to this simple and innovative operation solution, it is possible to obtain a dramatic structural simplification both of the individual selvedge-forming device of the invention - from which the guide and fixing means of the control rope are in fact removed - and of the general rope system which is required to operate multiple devices through the width of the forming cloth, which system is in fact fully dispensed with.
The individual selvedge-forming devices of the invention are fully independent and autonomous, so that their implementation on the loom requires no further action, in addition to the electrical connection of motors 1, which is not the simple positioning of the devices in their working position on the supporting crossbar whenever desired and the fixing of the same in the new position. With the device of the invention, useful space is therefore freed up on the loom and both device installation times and device repositioning times are further dramatically reduced when the textile item being woven is changed.
The second embodiment of the present invention, shown in figs. 4 and 5, maintains the same type of operation previously described with reference to the first embodiment, providing however a noticeable improvement of the driving and guiding means of posts M. The rack-and-toothed-wheel system is in fact replaced by a double-grooved pulley 2 and by two corresponding flexible ropes 3, of a non-extendable type, which cooperate therewith in the way detailed below to directly drive rods A parallel to posts M and connected therewith, so as to make up an extension thereof. Rods A, in a fully similar way to what occurred for racks C of the first embodiment, are laterally offset with reference to posts M to create between them the space sufficient to house the double-grooved pulley 2, and their mechanical connection with posts M comprises a hinge constraint, so as to allow modest mounting or operation misalignments between rods and posts without inducing inner stresses in said members and with no play in the longitudinal movement direction of the posts.
Pulley 2 is keyed onto the shaft of electric motor 1 which provides to operate it in alternate rotational motions, in a fully similar way to the drive of the toothed wheel of the first embodiment. The flexible ropes 3, each housed in a corresponding groove of pulley 2, are restrained in a central point thereof to the same pulley 2 - in diametrically opposite positions - so as to eliminate any possible mutual sliding between the ropes 3 and pulley 2. A particularly effective and quick system to join ropes 3 to pulley 2 is illustrated in figs. 5. According to this system, each of ropes 3 consists of two half-ropes 3' and 3" which have, on the pulley side, an eye-shaped end. The eye-equipped ends of the two half-ropes which make up each of ropes 3 are then arranged in recesses 6 and 7, respectively, formed on one side of pulley 2 and there securely fixed by screws (not shown) which are inserted in the terminal eye of each half-rope and which then engage with corresponding threaded holes 8. For this purpose, the entry mouths of recesses 6 and 7 open out on each of the two pulley grooves, respectively, at a cut-off portion of their inner delimitation wall; said entry mouths are suitably connected both with the bottom of the respective pulley groove and with the recess inside, to make up a continuous support without sharp edges to half-ropes 3' and 3" during the alternate movement of pulley 2.
At their free ends - facing opposite directions with reference to the common direction of rods A, as clearly visible in fig. 4B - flexible ropes 3 are then secured to the one and to the other, respectively, of rods A. In particular, each rod A is equipped with a lower anchoring site 4 and with an upper anchoring site 5. A first rope 3, and precisely the one having its ends facing down, connects the two lower anchoring site 4, whereas the other rope 3 connects the two upper anchoring points 5. Thereby, each of rods A is controlled in its shifting by one or the other of ropes 3, i.e. by the one which at that time is being tensioned, while the other rope acts as a guide for the rod itself, due to the fact that the rope system 3 is mounted perfectly taut or slightly pre-loaded so as to have absolutely no play. During the rotations of pulley 2, rods A hence always remain tangential to said pulley.
Since an end of rods A is constrained to posts M, preferably with a constraint comprising a hinge as seen above, the rods themselves have no degree of freedom and it is hence possible to eliminate with this solution any guide system of the same, which guide system was instead present of course, both in the prior art solution and in the first embodiment described above, in the form of sliding guides of the racks (C).
The frictions of the device manufactured according to this second embodiment of the invention are hence noticeably reduced over those typical of the first embodiment, both due to the removal of the guide system of racks C, and due to the fact that the frictions of the pulley/rope system described above are substantially negligible over those of the toothed wheel/rack system. For the same reasons mentioned above, the device of this second embodiment is further fully free from lubrication problems.
Since rods A work with axial loads and with no intermediate guides, it is naturally necessary that the same have great axial and flexural rigidity, together with as small a mass as possible, since they are members performing quick alternate motion. Preferred materials for the manufacturing of such rods are hence for example carbon fibres, fibre-reinforced plastic materials and the like.
From the preceding description it is evident how the device of the present invention has fully achieved the set objects. Over prior art devices, it has in fact a much simpler and more compact structure, with reduced friction and inertias. The device hence has lower manufacturing costs and greater operating efficiency. The direct drive of the device of the invention by electric motor 1 further allows high operating flexibility and flexibility of adjustment of the device itself, while the constant transmission ratio between motor revolutions and the shifting of rods A does not introduce any distortion of the imparted law of motion, which distortion is instead typical of traditional cam control systems, thereby contributing, also from this point of view, to greater device efficiency.
The present invention was described with reference to a preferred embodiment of the same, but it is clear that a number of variants and improvements may be imparted thereto by a person skilled in the art, without departing from the scope of the invention, which is in fact limited exclusively by the accompanying claims.

Claims

Warp yarn weaving device in a weaving loom, for selvedge formation or for leno heald weave at a cloth edge, of the type wherein two small heald assemblies, integral with corresponding, mutually parallel posts having alternate and symmetrical rectilinear motion, control the position of two corresponding assemblies of said warp yarns, characterised in that the motion is imparted to said posts by an electric motor having alternate rotational motions and apt to directly control, in an alternate and symmetrical rectilinear motion, a pair of driving rods parallel to the posts and connected thereto with no longitudinal play.
Warp yarn weaving device as in claim 1), wherein said rods comprise corresponding rack portions engaged with a same toothed wheel which is coaxial to said motor and keyed onto the operating shaft thereof.
Warp yarn weaving device as in claim 2), wherein said electric motor is mounted on a support base equipped with quick fixing means in a position at will on a loom crossmember, said support base comprising fixed sliding members to guide longitudinally said driving rods.
Warp yarn weaving device as in claim 1), wherein the control of said rods is actuated by a system of stays fixed with no play to said rods and brought into motion by at least one pulley, coaxial to said motor and keyed onto the operating shaft thereof, on which pulley said stays rest in a rolling condition with no sliding.
Warp yarn weaving device as in claim 4), wherein said pulley comprises two parallel grooves and said system of stays consists of a pair of flexible and non-extendable ropes, each of which is housed in a respective groove of such pulley and is secured to the same in a central position of the rope, in diametrically opposite pulley positions, the two free ends of each of said ropes being secured, with no play, to a pair of upper and lower anchoring sites, respectively, of said rods.
Warp yarn weaving device as in claim 5), wherein each of said ropes consists of two half-ropes which have eye-shaped pulley-side ends, said ends being secured by screw means to the lateral surface of said pulley, outside the groove housing said half-rope.
Warp yarn weaving device as in claim 6), wherein the two grooves of said pulley both have respective cut-off portions of their inner delimitation walls, in diametrically opposite pulley positions, apt to house the terminal length of said half-ropes, coming out from said grooves and towards said screw fixing means, said fixing means being housed within corresponding recesses formed on the lateral surface of the pulley and in communication with said cut-off portions of the inner wall of the grooves.
Warp yarn weaving device as in any one of claims from 4) to 7), wherein during the alternate rotational movement of the pulley said rods remain constantly tangential to the outer periphery of the pulley.
Warp yarn weaving device as in claim 4) or 5), wherein said electric motor is mounted on a support base equipped with quick fixing means in a position at will on a loom crossmember, said support base being free from fixed guide elements longitudinally guiding said control rods.