EP0854944A1 - Double-beam vertical loom - Google Patents

Abstract

A vertical loom which has the weaving plane arranged vertically or subvertically and comprises two opposite warp beams (2) arranged in the bottom part of the loom, two opposite weaving lines controlled in a synchronized and symmetrical manner by a single weave forming machine (A), two opposite cloth beams (8) arranged in the top part of the loom and a single loom drive mechanism comprising a motor/clutch unit (M), two twin transmission units (T) connected to the motor/clutch unit and suitable for transferring the movement thereof to a respective sley, and a control CPU.

Description

DOUBLE-BEAM VERTICAL LOOM

The present invention relates to a vertically arranged weaving loom, i.e. to a loom in which the weaving plane formed by the warp yarns lies vertically or sub-vertically. In particular the invention relates to a vertical loom of the abovementioned type which is able to weave at the same time a double cloth and hence is provided with a double warp beam and a double cloth beam.

Already from the mere reference to the subject-matter of the invention, the person skilled in the art is able to understand that the present invention falls within a decidedly new area of textile technology. Vertically arranged weaving looms have in fact been proposed in the past, with the obvious aim of reducing the plan dimensions of the loom and hence increasing the production capacity per unit of surface area allocated for this purpose, although they have never been effectively used on an industrial level.

This has been due to various factors: firstly, the fact that in a vertically arranged loom the heald frames lie substantially horizontally and it is therefore somewhat problematic to transfer to them the control movement of a weave forming machine (hereinafter simply called "weave machine"), since all the weave machines existing on the market are designed for operation in a vertical plane in which the control lever mechanisms emerging from the machine itself also lie. Leaving aside, therefore, for obvious cost-related reasons, the possibility of designing special-purpose weave machines arranged horizontally, the only remaining possibility is that of providing lever mechanisms suitable for transferring the control movements of the weave machine in a plane inclined at about 90° with respect to the normal operating plane of the machine itself, said lever mechanisms hitherto having proved to be fairly complex and unreliable.

Secondly, it must be noted that the known vertical looms have many unresolved problems as regards compensation and balancing of the forces; moreover, they have given rise to problems of a psychological nature, i.e. of acceptance by weaving operators who have obviously been faced with substantial changes in their working conditions compared to those which existed with conventional horizontal looms, but have not obtained any significant advantages in return for these changes.

The present invention has been developed precisely on the basis of a detailed analysis of the problems briefly outlined above, including both those of a strictly mechanical nature and those relating to the functionality of the machine from the point of view of the weaving operator, with the aim of developing a weaving machine which is able to exploit the hitherto untapped potential of vertical weaving looms and is thus suitable for use in the area of high- or very high-capacity production of fabrics with a relatively simple pattern, such as cloths for sheets, mattresses and the like.

Loom production technology has in fact directed its efforts, on the one hand, towards offering extremely high-performance looms, both in terms of machine productivity as well as fabric quality, weave complexity and flexibility of use, but, on the other hand, has not yet developed a suitably satisfactory design for looms with a high productivity per unit of surface area occupied, such as to allow the low- cost production of so-called "plain" fabrics, i.e. fabrics which although being of good quality consist of yarns which are traditionally less costly and delicate (typically cotton or synthetics) and have a simple weave, used in the production of articles for large-scale distribution. An increase in the productivity per unit of surface area occupied would in fact allow, for the same loom investment cost, a considerable reduction in the costs for the purchase or leasing of a building containing the weaving room and, what is even more important, a reduction in the energy costs necessary for maintaining temperature, humidity and dust conditions inside the weaving room suitable for guaranteeing the mechanical strength of the yarns and a high quality of the fabrics. The present invention intends to meet this requirement by providing a vertical loom which is able to effectively exploit the considerable advantages which weaving in a vertical or sub-vertical plane is able to offer and which hitherto, at least from the point of view of actual application on an industrial level, it has not been possible to achieve at all.

This aim is achieved, according to the present invention, by means of a vertical loom of the type in which the weaving plane lies vertically or sub-vertically and comprising two opposite warp beams arranged in the bottom part of the loom, two opposite cloth beams arranged in the top part thereof and two opposite weaving lines, respectively arranged between said warp beams and said cloth beams and each comprising a set of heald frames and a sley provided with a reed, said weaving lines being controlled in a synchronized way by a single loom drive mechanism.

According to a preferred characteristic feature of the invention, said drive mechanism comprises a single control CPU, and a single motor/clutch unit driving in a synchronized way two transmission units, each apt to move a respective sley, and a single weave forming machine apt to control the movement of said two sets of heald frames.

As is already obvious from this definition of the novel double- beam loom of the present invention, it is possible to achieve all the alternating movements of this machine, i.e. that of the sley with associated reed, the heald frames and the control leverage of the latter, in a nearly perfectly balanced manner, such that the dynamic stresses transmitted to the base of the machine are substantially reduced, ensuring exceptionally stable operation of the loom.

The various characteristic features and the numerous advantages of the loom according to the present invention will nevertheless emerge more clearly from the following detailed description of a preferred embodiment of the loom itself, in which:

Fig. 1 is a schematic overall side view of a preferred embodiment of the double-beam vertical loom according to the present invention; Fig. 2 is a front view of the loom shown in Fig. 1 ; Fig. 3 is a schematic cross-sectional view of the weft insertion zone, showing the dimensions of the weft launching channel in conventional looms and in the loom of the present invention;

Figs. 4 and 5 are schematic plan views showing, respectively, the space occupied, inside a typical weaving room, by conventional horizontal looms and by vertical looms according to the present invention (all the measurements being expressed in mm). In Fig. 1 it is possible to clearly see the various parts which form the loom according to the present invention. In the description which follows, the structure of only one of the sides of the loom will be described in detail, it being understood that this description is symmetrically repeatable for the other side of the loom. The body of the loom is formed by a strong central frame 1 which has mounted on either side of it the single devices forming two complete weaving lines, which are arranged opposite each other and perfectly symmetrical with respect to a central vertical plane of symmetry. Starting from the bottom zone of the loom, it is possible to note the warp beams 2, drive bars 3 and yarn-pulling bars 1 1 for the warp yarns with, installed between them, the warp stop devices 12, heald frames 4, sleys with reed 5, take-up cylinders 7 for the newly formed cloth 6 and, finally, cloth beams 8. The loom also comprises a drive mechanism consisting of a single control CPU (not shown), a single main motor/clutch unit M, and two twin transmission units T, which are both connected to the motor/clutch unit and are apt to transmit the movement thereof to a respective sley, through a cam system apt to transform the rotary movement of the motor/clutch unit M in the alternately movement of the sley.

Preferably, said two transmission units are housed in one single gear box, with the advantage of having only one common lubrication system, each transmission unit being positioned respectively at the left and right side of a central gear wheel and mated therewith, said central gear wheel being in turn driven by said motor/clutch unit M.

In an embodiment of the present invention, one of said transmission units is also apt to transmit the movement of the motor/clutch unit M to a weave forming machine A, while the other transmission unit is apt to transmit the movement to two identical transmission units (not shown in the drawings) positioned on the other side of the loom. In these way, it is possible to drive the sleys at both sides thereof, highly reducing the torsional stresses on these devices, which can therefore be made with a lighter structure, allowing a favourable reduction of power consumption.

All the above said elements are known per se and are therefore not described in greater detail for the sake of simplicity. In the drawings, moreover, the weft insertion system, which is of the conventional, preferably air type, is not shown. Although, in fact, the double beam loom according to the present invention may be equipped with weft insertion devices both of the gripper and air or water type, it is able to make best use of its potential precisely with an air-type weft insertion system, to which exclusive reference will be made below, without thereby the invention necessarily being understood as limited thereto. As can be seen from Fig. 1 , the structure of the double-beam loom according to the present invention extends in the vertical direction, with the warp beams 2 arranged in the bottom part of the machine and the cloth beams 8 arranged along the vertical of the beams 2, above the frame 1 and resting on the latter by means of pairs of motor-driven rollers 9 and 10, which allow winding of the fabric onto the cloth beam

8 to be performed at a constant linear speed independently of the diameter reached by the beam itself. In particular, the winding roller 9 has a speed of rotation slightly greater than that of the take-up cylinder 7 and is provided with a suitable friction device, so as to keep the fabric arriving onto it at the desired degree of tensioning. In turn, the pushing roller 10 has a speed of rotation slightly greater than that of the winding roller 9 and is provided with its own adjustable friction device, thus allowing, owing to suitable calibration of the friction device, the required degree of tensioning of the cloth beam 8 to be achieved. As an alternative to the winding system of the above described cloth beam, it is obviously possible to use also the conventional system which comprises a carrier drive roller, coaxial with the beam 8, which is pivotably hinged in a fixed position on the frame 1 , as illustrated in Fig. 2. The warp beams 2, take-up cylinders 7 and rollers 9 and 10 can be moved by the same main motor/clutch unit 7, but are preferably equipped with independent motor units, electronicaly controlled to maintain the desired travelling speed and tensioning of the fabric.

The weaving zone comprised between the yarn-pulling bar 1 1 and the reed 5 extends in a vertical or sub-vertical plane and consequently the heald frames 4 lie in a horizontal or near-horizontal plane. This makes it possible to use a very simple system for supporting and guiding the heald frames. The individual heald frames are in fact arranged on top of one another and make mutual contact via plates of anti-friction material mounted thereon; the heald frames are then kept laterally in the required position by means of common lateral guides. This arrangement, besides making the frame guiding system more streamline, also enables the said frames to be made with a much more economical and lightweight structure, besides facilitating and speeding up considerably engagement and disengagement thereof from the loom.

The maximum number of heald frames for each weaving line is preferably a low number, for example from four to a maximum of eight heald frames per line. From a first point of view, this number of heald frames is in fact entirely sufficient for the type of fabrics for which the loom according to the present invention has been specifically designed. From a second point of view, with such a small number of heald frames it is possible to provide a symmetrical and very compact geometry for the shed inlets, reducing the extent of travel of the sley and of the heald frames and correspondingly the tension imparted to the warp yarns during opening of the shed. The reduced travel of the heald frames also contributes to a reduction in the stresses occurring thereon, due to the accelerations of their alternating movement and consequently makes it possible to adopt more streamline and lighter structures for the frames, with the advantage of a reduction in the power consumption associated with their movement. Finally, the reduction in the travel of the frames results in a corresponding reduction in the cross-sectional area of the inlets comprised between the reed and the fabric forming line which, when the inlets are completely open, is preferably about 40/60% less than the similar cross-section in ordinary horizontal looms, as schematically illustrated in Fig. 3, in which the simply shaded zone indicates the cross-sectional area of the inlets for conventional looms, while the cross-hatched area indicates the corresponding area for the loom according to the invention. As a result of this contrivance, therefore, the compressed-air flow rate needed to launch the weft across the weft is reduced considerably, thus achieving from this point of view a fairly significant reduction in energy costs.

The movement to the heald frames 4 is imparted by a lever control system, operated by a single weave machine A located at one of the two ends of the loom. This system forms the subject-matter of the jointly pending Italian patent application No. MI95A002080, the contents of which are understood as being incorporated herein for the sake of reference. Said control system functions such as to cause symmetrical movements of the corresponding heald frames on the two opposite weaving lines. In other words, the loom is designed to weave identical fabrics both on one side and on the opposite side of the loom, even though obviously different yarns or different weft or warp densities may be used during formation of the fabrics on the two sides of the loom. It is also important to underline the fact that, owing to this symmetrical and hence balanced movement of the heald frames, in the case of non-cloth weaves, i.e. in weaves which have a front and rear face of the fabric, the fabric is always presented in the same manner (normally with the front face directed towards the weaving operator) on the two sides of the loom. As a result, in addition to the obvious fact that the operator is able to examine the fabric face which is of greatest interest for quality control purposes, it is ensured that there is the same degree of adherence of the fabric on the various drive rollers and tensioning cylinders of the loom and, therefore, in practice the same type and quality of winding of the fabric onto the two cloth beams 8.

The movement is transmitted to the sley, and hence to the reed 5, by the aforementioned transmission units T, each of which comprises a cam system for transmission of the movement, instead of the more conventional system of connecting rods and cranks. This makes it possible to modify with great ease, i.e. merely by replacing the cams, the movement cycle of the reed. According to a preferred characteristic feature of the looms according to the present invention, said movement cycle comprises an inactive period during the part of the cycle wherein the weft is inserted into the open shed, so as to allow easy and correct insertion of the weft when the above-described geometrical arrangement of the shed inlets - characterized by a shorter travel distance of the frames and hence a smaller cross-sectional area of the shed itself - is adopted. The particular structure of the loom according to the present invention, which is at the same time simple, compact and extremely accessible, has enabled the inventor to provide a loom cleaning system with removal of the tufts of dust which continuously form in the parts of the loom underlying the weaving zone and the zone of the warp stop device. These tufts of dust, in fact, create not insignificant problems both as regards the efficiency of the loom, since they may cause breakage of the warp yarns and hence corresponding stoppages of the loom, and as regards the quality of the fabric, since they may become trapped and drawn along by the warp yarns and "woven" with them, leaving visible signs on the fabric even after their removal. This cleaning system can replace the system currently used in weaving rooms consisting of travelling cleaning devices, and therefore eliminate the main disadvantages thereof, such as: the creation of dust in the environment; the removal of only that part of the dust which is situated outside the looms, leaving unaffected the dust which instead becomes lodged in the internal parts thereof; the use of considerable volumes of humid ambient air causing the tackiness of the tufts. Said cleaning system is described in detail in the jointly pending Italian patent application No. MI95A002081 , the contents of which are understood as being incorporated herein for reference.

Finally, it is important to note the particular relative arrangement of the warp beam 2, yarn-guiding bar 3 and yarn-pulling bar 1 1 which last is of the driven type and is inserted between the yarn-guiding bar 3 and the heald frames 4. Said arrangement is such that it ensures that the section of warp yarns arriving on the yarn-pulling bar 1 1 is substantially perpendicular to the section of yarns leaving it and moreover, as already mentioned, that the shed inlets have a symmetrical geometry. This makes it possible to achieve significant advantages during operation of the yarn-pulling bar 1 1 , and during cleaning of the dust from the loom, as will be explained more clearly below. The yarn- pulling bar 1 1 has preferably a small diameter (of the order of a few centimetres, preferably 2 cm) so as to leave ample space for the weaving operator to freely operate during the loom setting-up operation; to ensure that the bar is sufficiently rigid, said bar is provided with a certain number of supports, or, alternatively, it is made of materials with a high rigidity such as, for example, carbon fibres. The advantages which are achieved with the novel loom structure illustrated above are numerous and of considerable technical and industrial value.

A first obvious advantage consists in the extraordinary saving in the amount of space occupied by the loom for the same production output, or, from another point of view, the considerable increase in productivity per unit of surface area allocated for installation of the looms. The space occupied on the horizontal plane by the loom according to the present invention is in fact only 10% more than that of an ordinary loom, with a productivity, however, which is doubled and hence increased by 100% . There is therefore an increase in productivity per individual machine, for the same space occupied, of more than 80% . Even taking into account the greater space for passageways which must be left on both sides of the looms according to the present invention, there is nevertheless a very large increase in the productivity per unit of surface area occupied, equivalent to about 75%, as can be seen from a comparison of Figs. 4 and 5 which show the installation lay-out of, respectively, a weaving room equipped with 32 looms of the conventional type (Fig. 4) and a room equipped with the same number of double-beam vertical looms according to the present invention (Fig. 5). If a comparison is made with the horizontal looms provided with large cloth-winding beams, similar to those with which the looms according to the present invention are equipped, the increase in the productivity per unit of surface area occupied even exceeds 100%.

A second notable advantage lies in the fairly high stability of the loom, a stability which is derived from its perfectly symmetrical structure, both from the point of view of the location of the individual components, and from the point of view of movement of the moving parts. As already mentioned in fact, all the parts which perform an alternating movement, and in particular the lever mechanism operating the heald frames and the heald frames themselves, move simultanously in more or less opposite directions (it must not be forgotten that the heald frames lie horizontally or almost horizontally) and therefore balance each other. This makes it possible to achieve a drastic reduction in the vibrations and consequently a greater stability of the loom even at very high operating speeds.

A positive consequence of the stability of the novel loom and the significant reduction in the vibrations due to the alternating masses in movement is also the reduction in noisiness. This occurs in relation to both a single machine and a plurality of machines grouped together in a weaving room; in the latter case, in fact, the considerable height of the loom (about 2 m) makes it possible to form a sound barrier capable of dampening the noise waves emitted by the neighbouring looms, with a general reduction in the noisiness which, it has been calculated, may oscillate between 2 and 5 dB, whereby a reduction of 3 dB is equivalent to a reduction by half of the acoustic intensity.

A fourth advantage consists in the low cost of manufacturing the loom according to the invention. In this loom, in fact, many components are single component and are simultaneously used for the two opposite weaving lines. In particular, there is only one main motor/clutch unit M, a single transmission gear box T, a single weave forming machine A and a single control CPU. This is permitted by the fact that the control systems serving the two weaving lines are entirely identical and it is therefore possible to duplicate them, either mechanically (for the drive mechanism and weave machine) or electronically (for the control CPU), so as to obtain the desired operation of the entire loom. In this way the overall cost of the loom is only about 50% greater than that of a conventional loom, thus achieving from this point of view as well an extremely interesting result. A fifth advantage is obtained in relation to the energy consumption. On the one hand, in fact, the reduction in the number of moving parts involved, compared to those existing in two conventional horizontal looms, their symmetrical and hence balanced movement, and finally the reduction in the distance traveled by the heald frames and the reeds make it possible to use a main motor with a power and hence consumption less than the consumption of the two motors of two corresponding conventional looms. On the other hand, however, it must be pointed out that the aforementioned reduction of up to 40-60% of the cross-sectional area of the inlets forming the shed makes it possible to reduce considerably the volume of the weft yarn launching channel, thus resulting in a considerable saving also in the amount of compressed air used for insertion of the weft. A sixth advantage depends on the position and the operation of the cloth beams. As has been seen above, in fact, these beams are located in the top part of the machine and, in a preferred embodiment, they are made to rotate not as occurs in conventional looms, by causing their axis to rotate, but instead by arranging them so that they rest on the pair of rollers 9 and 10 which are driven at different speeds. Some important advantages are achieved as a result. First of all, the beam may be wound also up to very high diameters, since it is not located inside the loom or bound by the position of its axis; it is therefore possible to wind variable lengths of cloth in accordance with the purchasers requirements. Another advantage arises from the fact that the cloth is driven at its periphery and not in the centre; it is therefore no longer necessary to gradually reduce the speed of winding of the beam as its diameter increases, with the advantage of a greater simplicity of the machine; as a result of the different speeds of rotation of the two rollers 9 and 10, it is also possible to obtain a more uniform packing of the fabric during winding. A further advantage then consists in the fact that the operation of removing the full cloth beams and installing the corresponding empty beams may be performed from above, for example with a bridge crane, without therefore interrupting the weaving operations or hindering the movement of the weaving operators around the looms, a fact which contributes to an increase in the efficiency and productivity of the loom according to the present invention. A seventh advantage depends, finally, on the particular relative spatial arrangement of the yarn-guiding bar 3 and the yarn-pulling bar 1 1 described above. Since, in fact, the compensating movement of the yarn-pulling bar 1 1 , during opening and closing of the shed, occurs parallel to the direction of the weaving plane (arrow F), this movement is substantially perpendicular to the section of warp yarns comprised between the yarn-pulling bar 1 1 and the yarn-guiding bar 3. Since it is precisely in this section that the warp stop device 12 is installed, there are three important advantages of this arrangement. Firstly, owing to the fact that the compensating movement of the yarn-pulling bar 1 1 does not cause, as instead occurs in conventional frames, alternating rubbing of the warp yarns inside the drop wires of the warp stop device and there is therefore neither abrasion of the yarns, nor emission of the corresponding dusty material due to said abrasion. A second advantage is obtained, on the other hand, owing to the fact that the albeit smaller quantity of dust which forms in the region of the drop wires of the warp stop device, or which is conveyed into the vicinity thereof, is easily detached from said wires as a result of the beating movement of the warp yarns caused by displacement of the yarn-pulling bar 1 1 in the direction of the arrow F and falls into the underlying zone where it is immediately collected by the automatic cleaning system described in the aforementioned patent application. Finally, a third advantage is obtained owing to the fact that the sharp angle formed by the warp yarns in the region of the yarn-pulling bar 1 1 and the jerking movement of the latter facilitate the immediate dropping of the drop wire corresponding to any broken warp yarns, as soon as a breakage occurs, avoiding the weaving of warp yarns which are not perfectly taut. All of the numerous advantages briefly mentioned above, however, relate strictly to the mechanical structure of the loom and the associated actuating devices. It must therefore also be pointed out that the double-beam loom according to the present invention results in even more significant and particular advantages with regard to the human factor, i.e. the operator supervising the weaving operation, since her/his work is made much simpler and easier. The loom according to the present invention has in fact been developed precisely with a view to achieving a marked improvement, from an ergonomic point of view, in the position of the operator, designed to achieve a marked reduction both in the loom preparation and/or repair times and the fatigue of the operator.

A first advantage consists in the possibility, not present in conventional machines, of the operator being able to monitor all the working zones from a single position. In the loom according to the present invention, in fact, he has the entire weaving line in front of him, from the warp beam to the cloth-winding beam, while in the case of conventional machines on one side (rear side) he is able to monitor only the warp beam, while on the other side (front side) he is able to monitor only the weaving zone.

A second advantage, arising directly from the previous one, is the possibility of performing repair of the broken warp yarn in a single operation and on one side only of the loom, rather than in two stages, interrupted by displacement of the operator from one side of the frame to the other, as instead occurs in conventional machines.

A third advantage consists in the more comfortable position of the operator during each type of maintenance or repair operation involving the yarns and loom. In the loom according to the present invention he is in fact always in an erect or semi-erect position, with the working zone at a very short distance and at a confortable height, seen the particular position of the weaving zones, soon above the warp beams 2_*. On the other hand, in conventional looms, the operator must assume very uncomfortable positions during the various repair operations involving the warp yarns, bending forwards towards the centre of the loom with inclination of the top part of the body by as much as 40° or 50° with respect to the vertical.

A fourth advantage, finally, consists in the extraordinary compactness of the looms according to the present invention. In fact, referring again to Figs. 4 and 5, it can be easily stated that a worker supervising 32 conventional machines illustrated in Fig. 4, must monitor a rectangular zone of the room, the most distant points of which lie at about 36.56 m from each other (Fig. 4). This distance therefore represents the distance which the operator must cover in order to monitor the machines assigned to him. In the case of the looms according to the present invention, shown in Fig. 5, for the same number of cloths being processed (32 more specifically), this distance becomes much smaller, being equivalent to about 20.22 m. It is obvious, therefore, that that portion of the fatigue which the operator is subject to as a result of walking around inside the area of the weaving room monitored by him, will be reduced by more than 40%, with an extraordinarily positive result therefore.

In the above text, a description of all those mechanisms, which allow actual operation of the loom and are per se perfectly known to the person skilled in the art, has been deliberately omitted; instead, for the purposes of more immediate comprehension, a description is merely given of the essential lay-out of the new geometry which, in the loom according to the present invention, has been assigned to these known devices, a geometry which incorporates the true inventive concept of the invention. It seems appropriate, however, to make at least specific reference to the arrangement of the weft feeding systems - including the bobbin- carrying creels, the weft feeders and the main weft launching nozzles - with respect to the loom according to the present invention. As regards the above, it is obvious, in fact, that the two yarn feeding systems necessary for operation of the loom according to the present invention are normally arranged at the opposite ends of the loom, i.e. usually on the left of each respective weaving line; with this arrangement, in fact, perfect symmetry is achieved between the two opposite weaving lines, with an identical fabric forming process on both sides of the loom. However, it is obviously possible, if the lateral dimensions need to be further reduced at one of the two ends of the loom, to arrange the yarn feeding systems both on the same side of the loom. In order to do so, it is merely necessary to reverse the feeding direction of the secondary nozzles in one of the two weaving lines and obviously also the position of the individual loom accessories associated with the weft insertion operation. In this latter case, the operator will have the minor disadvantage of having to remember that, on one side of the loom, insertion of the weft is performed from left to right, as usual, while on the other side of the loom insertion of the weft will be performed from right to left.

For a definition of the structural parts of the double-beam loom according to the present invention which have instead involved specific innovations, the reader should refer to the text of the aforementioned patent applications, filed on the same date as the present application and in the name of the same Applicant, in which these innovations have been specifically illustrated and described in accordance with that indicated above in each case.

Claims

Claims 1 . A vertical loom of the type in which the weaving plane lies vertically or sub-vertically, characterized in that it comprises two opposite warp beams (2) arranged in the bottom part of the loom, two opposite cloth beams (8) arranged in the top part thereof, and two opposite weaving lines, respectively arranged between said warp beams and said cloth beams and each comprising a set of heald frames (4) and a sley (5) provided with a reed, said weaving lines being controlled in a synchronized way by a single loom drive mechanism.

2. A vertical loom as claimed in claim 1 , wherein said drive mechanism comprises a single control CPU, and a single motor/clutch unit (M) driving in a synchronized way two transmission units (T), each apt to move a respective sley (5), and a single weave forming machine (A) apt to control the movement of said two sets of heald frames (4).

3. A vertical loom as claimed in claim 2, wherein said transmission units (T) are housed in a single gear box, at the two sides of a central gear wheel with which they are mated, said gear wheel being driven by said motor/clutch unit (M).

4. A vertical loom as claimed in claim 2, wherein one of said transmission units (T) is apt to move said weave forming machine (A), while the other one of said transmission units (T) is apt to move two identical transmission units positioned on the other side of the loom, so a to impart a balanced driving to the sleys (5).

5. A vertical loom as claimed in claim 2, wherein said transmission units (T) comprise at least one cam system, apt to determine the alternate movement of the sleys (5).

6. A vertical loom as claimed in claim 5, wherein the synchronized and symmetrical movement of the sleys (5) and of the associated reeds involves an inactive period during the part of the weaving cycle wherein the weft yarn is inserted.

7. A vertical loom as claimed in claim 1 , wherein each of the cloth beams (8) rests on a pair of driving rollers (9, 10) .

8. A vertical loom as claimed in claim 7, wherein said driving rollers comprise a winding roller (9) with a peripheral speed slightly greater than the peripheral speed of the take-up cylinder (7) and a pushing roller ( 10) with a peripheral speed slightly greater than that of the winding roller (9).

9. A vertical loom as claimed in claim 8, wherein said driving rollers (9, 10) are each provided with an adjustable friction system.

10. A vertical loom as claimed in any one of the preceding claims, wherein the heald frames (4) are arranged in a horizontal or almost horizontal plane.

1 1 . A vertical loom as claimed in claim 10, wherein the heald frames (4) rest one on another through contact plates of anti-friction material fixed thereto, inside common lateral guides.

1 2. A vertical loom as claimed in any one of the preceding claims, wherein the cross-sectional area of the shed comprised between the reed and the fabric forming line, when the shed inlets are completely open, is about 40-60% less than that of conventional looms.

1 3. A vertical loom as claimed in any one of the preceding claims, wherein the warp yarns coming from each warp beam (2) are deviated by a fixed yarn-guiding bar (3) in a horizontal or almost horizontal plane and then deviated again, substantially at a right-angle, in a vertical or sub-vertical plane coinciding with the weaving zone, by a driven yarn-pulling bar (1 1 ).

14. Vertical loom as claimed in claim 1 3, wherein said driven yarn-pulling bar ( 1 1 ) performs an alternating movement in a direction parallel to said weaving plane in a manner coordinated with the shed opening and closing movement.

1 5. A vertical loom as claimed in claim 1 3, wherein said yarn- pulling bar (1 1 ) has a diametr of about 2 cm and is provided with a plurality of supports along its length.