Yarn carrier for weaving looms

Abstract: A yarn carrier for weaving looms, over which the warp yarns supplied by one or more beams and directed towards the fabric forming zone of the loom pass, has two or more adjacent cylinders with the same diameter (1a, 1b) mounted idle on a respective twisting bar (4a, 4b), the axis of which is parallel to and at a distance from the fixed axis of oscillation (7) of the yarn carrier. Said support bars (4a, 4b) are mounted oscillating on said axis (7) by means of pairs of levers (5a, 5b and 6a, 6b) which are pivotably mounted on fixed supports of the loom, said support bars (4a, 4b) being able to be locked together in rotation.

Description: The present invention relates to a yarn carrier for weaving looms which is constructed so as to allow more efficient supporting of the warp yarns and improved compensation of the tension thereof, when the looms are equipped with a single beam or, respectively, with several beams arranged alongside each other. It is known from EP 0 204 233 A, which discloses a yarn carrier according to the preamble of claim 1, that in weaving looms which produce double-width fabric, or, in any case, in looms which are very long, the fabric may consist of two separate or attached pieces, with the warp yarns which are unwound from two separate beams arranged alongside each other, in which case the yarn-carrying cylinder essentially consists of a pair of idle cylinders oscillating with respect to a fixed axis and supported in the middle of the loom as well as on the two external shoulders. Alternatively, the fabric may consist of a single piece, with the warp yarns unwound from a single beam, or two "twin" beams arranged alongside each other, in which case the yarn-carrying cylinder essentially consists of a single idle cylinder oscillating with respect to a fixed axis and supported at the two ends of the shoulders of the weaving loom. Moreover it is also know that the moment of inertia of the yarn-carrying cylinder has a negative effect, which is proportional to the length of the loom or to the horizontal distance between the two side levers supporting the cylinder itself, since with a high moment of inertia it is not possible to limit the cylinder deflection induced by the load of the yarns. The yarn-carrying cylinders thus constructed, in accordance with the known art, therefore have the defect of negatively influencing the weaving process by introducing, on the warp yarns, tension peaks which cause continuous breakage of the yarns themselves on account of the high moment of inertia both during rotation of the cylinders about their longitudinal axis and during their oscillation with respect to their fixed axis. It is therefore obvious that, in the case of a very "long" loom, the problem of the moment of inertia of the yarn carrier becomes critical in the case of single-piece fabrics if operation is being performed with a single-cylinder yarn carrier, whereas it is less critical, although not entirely negligible, in the case of fabrics consisting of two separate pieces, with a "split" yarn carrier. The present invention now aims to solve the abovementioned problem by providing the yarn carrier with a configuration which is extremely versatile for the purposes of supporting the yarns and compensating the tension thereof and thus favouring uniform intertwining between weft and warp over the whole length of the loom. In particular, the invention relates to a yarn carrier which is suitable for a double-width and two-piece loom, but may be adapted, if necessary, for the production of a single piece. The invention solves the problem posed by means of a yarn carrier for weaving looms over which the warp yarns supplied by one or more beams and directed towards the fabric forming zone of the loom pass consisting of at least two adjacent cylinders with the same diameter, characterized in that said cylinders are mounted idle on a respective support bar, the axis of which is parallel to and at a distance from the fixed axis of oscillation of the yarn carrier; in that said support bars are mounted oscillating on said axis by means of pairs of levers which are pivotably mounted on fixed supports of the loom and in that said support bars may be locked together in rotation. In a suitable manner, elements for deviating the warp yarns at the adjacent ends of said cylinders are also provided. In a particular embodiment of the invention for a double-width and twin-beam loom, the yarn carrier comprises a pair of cylinders which are respectively connected to the resilient reaction system present on each side of the loom, the corresponding support bars of which may or may not be locked in rotation by means of a removable joint, preferably of the flanged type with a screw-type connection, which is located in the middle of the loom. The invention is now described in greater detail with reference to the accompanying drawings, which illustrate a currently preferred embodiment thereof with a yarn carrier consisting of two cylinders and in which: Fig. 1 is a perspective view of the yarn carrier according to the invention applied to a weaving loom consisting of two beams arranged alongside each other, said yarn carrier being located above the beams themselves; Fig. 2 shows a detail of a type of joint provided between the two cylinders of the yarn carrier according to Fig. 1; Fig. 3 shows a device for deviating the warp yarns in the region of said joint and a variation of embodiment of the joint itself; Fig. 4 shows the yarn carrier according to the present invention applied to a loom which has two beams mounted alongside each other and illustrates the operation thereof; and Fig. 5 shows the yarn carrier according to the invention applied to a loom which has a single beam mounted and illustrates the operation diagram thereof. With reference to the drawings, the yarn carrier according to the invention consists, in the embodiment shown, of a pair of external cylinders 1a, 1b over each of which the yarns F unwound from the beams 2a, 2b of the loom travel and which are operated in a known manner by the unwinding device 3a, 3b. Each cylinder 1a, 1b of the yarn carrier 3a, 3b is mounted idle on a respective support bar 4a, 4b mounted parallel to and at a distance from the axis 7 of oscillation of the yarn carrier by means of pairs of levers, 5a, 5b, on the outer sides of the loom and, 6a, 6b, close to the middle of the loom itself, respectively. The support bars 4a and 4b are arranged alongside each other and the levers 5a, 5b and 6a, 6b are pivotably mounted on the loom by means of suitable supports. The support bars 4a, 4b are also connected to the resilient reaction system 8a, 8b arranged on the sides of the loom, at the end of each support bar 4a, 4b. The side levers 5a, 5b are pivotably mounted on the loom in a known manner, whereas the levers 6a, 6b in the centre of the loom are mounted, oscillating about the axis 7, on a support of the fixed structure of the loom and may be joined together in a permanent or removable manner by means of a joint 10 (see Fig. 2). Said joint may be provided, instead of between the levers 6a and 6b, as shown in Fig. 2, directly between the support bars 4a and 4b, in accordance with the embodiment shown in Fig. 3: in this case the flanged solution with fixing screws is compact, with the advantage of a smaller deviation of the yarns, which in any case must be provided, in accordance with the invention, between each cylinder of the yarn carrier, i.e. in the example illustrated, in the middle of the loom. In this connection Fig. 3 shows how, in the region of the joint between the two adjacent portions of the yarn carrier, deviation elements 11 for the yarns are provided integral with the fixed structure of the loom or, alternatively, with the levers 6a, 6b. Although illustrated and described above in connection with the embodiment consisting of two cylinders, the yarn carrier according to the invention may comprise - as already indicated - three or more adjacent cylinders, mounted idle on respective support bars, which may be locked together in rotation, so as to transmit the twisting torque between each bar and the adjacent bars. The use of the yarn carrier according to the invention, which is constructed with two or more cylinders which are detached, but can be joined together by means of the joint 10 and are also supported by a series of intermediate levers, results in important advantages. Firstly, a yarn carrier formed by a series of modules, the transverse dimensions of which are significantly smaller, is obtained: this allows a considerable improvement in the performance of the yarn carrier itself, the inertia of which, thus greatly reduced, tends to be uninfluential during the fabric forming steps. In the case of a double-width loom, by simply connecting or disconnecting the joint 10, it is possible to adapt the yarn carrier so as to obtain the best operating performance of the loom with a single beam (Fig. 5) or with a twin beam (Fig. 4), for the weaving of one piece or two pieces (both separate and attached), thus resulting in effective and rational compensation of the tension of the warp yarns in both cases: in the case of a single piece, there being basically a single continuous yarn carrier operating uniformly and, in the case of a double piece, two separate yarn carriers, one for each piece, operating independently and as required for weaving of the two pieces. It is understood that other embodiments of the yarn carrier for weaving looms, different from those described, could be carried out. These embodiments obviously fall within the present invention.

Claims: Yarn carrier for weaving looms over which the warp yarns supplied by one or more beams and directed towards the fabric forming zone of the loom pass consisting of at least two adjacent cylinders with the same diameter (1a, 1b), characterized in that said cylinders (1a, 1b) are mounted idle on a respective support bar (4a, 4b), the axis of which is parallel to and at a distance from the fixed axis of oscillation (7) of the yarn carrier; in that said support bars (4a, 4b) are mounted oscillating on said axis (7) by means of pairs of levers (5a, 5b and 6a, 6b) which are pivotably mounted on fixed supports of the loom, and in that said support bars (4a, 4b) may be locked together in rotation. Yarn carrier for weaving looms as claimed in Claim 1, wherein elements (11) for deviating the warp yarns (F) are provided in the region of the adjacent ends of said cylinders (1a, 1b). Yarn carrier for weaving looms as claimed in Claim 1, of the double-width twin-beam type, wherein the yarn carriers comprises a pair of cylinders (1a, 1b) respectively connected to the resilient reaction system (8a, 8b) present on each side of the loom, the corresponding support bars (4a, 4b) of which may or may not be locked together in rotation by means of a removable joint (10), preferably of the flanged type with a screw-type connection, located in the middle of the loom. Yarn carrier for weaving looms as claimed in Claim 1, wherein said support bars (4a, 4b) are locked together in rotation by means of removable joints (10). Yarn carrier for weaving looms as claimed in Claim 4, wherein said joints (10) operate directly between the support bars (4a, 4b). Yarn carrier for weaving looms as claimed in Claim 4, wherein said joints (10) operate between said mounting levers (6a, 6b).

Inventors: CASAROTTO GIUSEPPE, CASAROTTO, GIUSEPPE
Applicants: PROMATECH SPA, PROMATECH S.P.A.
Application year: 1999
Main classification: D03D49
IPC codes: D03D49