Circular weaving machine

Abstract

A circular weaving machine has warp-tape guide elements arranged around a circular reed to supply a multiplicity of warp tapes. Weaving-shed forming devices group the fed warp tapes into two warp-tape groups and impart thereon mutually opposed alternating movements, with the result that a weaving shed is opened and closed between the two warp-tape groups. A weaving shuttle moves on an orbit in the opened weaving shed and, in the process, introduces a weft tape from a weft-tape bobbin carried thereby into the weaving shed, with the result that a fabric is formed. The fabric is drawn off through a weaving ring. The weaving shuttle keeps the bobbin axis of the weft-tape bobbin at an angular position which deviates by at most +/15, preferably at most +/10, from a normal to a surface which contains the geometric connecting lines between the warp-tape guide elements and the weaving ring.

Claims

1. A circular weaving machine comprising warp-tape guide elements which are arranged around a circular reed of the circular weaving machine in order to supply a multiplicity of warp tapes to the circular weaving machine, comprising weaving-shed forming devices which divide the supplied warp tapes into two warp-tape groups and impart mutually opposed alternating movements to the two warp-tape groups, with the result that a weaving shed is opened and closed between the two warp-tape groups, comprising a weaving shuttle which moves on an orbit in the opened weaving shed in order to draw off, during its circulation, a weft tape from a weft-tape bobbin it carries, introducing it into the weaving shed, with the result that a fabric is formed, and comprising a weaving ring through which the fabric is drawn off, wherein the weaving shuttle keeps the bobbin axis of the weft-tape bobbin at an angular position which deviates by at most +/15, from a normal to a surface which contains the geometric connecting lines between the warp-tape guide elements and the weaving ring.

2. A circular weaving machine according to claim 1, wherein the weaving shuttle keeps the bobbin axis of the weft-tape bobbin essentially at right angles to the surface.

3. A circular weaving machine according to claim 1, wherein the surface forms essentially a circular ring surface.

4. A circular weaving machine according to claim 3, wherein the circular reed is configured as a circular cylinder.

5. A circular weaving machine according to claim 1, wherein the surface forms essentially a truncated cone surface.

6. A circular weaving machine according to claim 5, wherein the circular reed is configured as a truncated cone.

7. A circular weaving machine according to claim 1, wherein the weaving ring is arranged inside the circular reed.

8. A weft-tape bobbin in a circular weaving machine according to claim 1, wherein, with the weft-tape bobbin being full, the bobbin diameter (D) is larger than the bobbin length (L).

9. A weft-tape bobbin according to claim 8, wherein the weft-tape bobbin is a bobbin with plastic tapes wound around it.

Description

(1) The invention is now illustrated in further detail on the basis of exemplary embodiments with reference to the drawings. In the drawings:

(2) FIG. 1 shows a schematic sectional view of a first embodiment of a circular weaving machine according to the invention;

(3) FIG. 2 shows a schematic perspective view of the circular reed and of the weaving shuttles of the circular weaving machine of FIG. 1, which circulate in the circular reed; and

(4) FIG. 3 shows a schematic sectional view of a second embodiment of a circular weaving machine according to the invention.

(5) For the sake of better clarity, FIG. 1 and FIG. 2 schematically show, in a manner not true to scale, the elements of a first embodiment of a circular weaving machine 1 according to the invention which are essential to the invention. The circular weaving machine 1 comprises a plurality of warp-tape guide elements 2 which are configured as length adjustment compensators and, in each case, comprise a spring bar and an eyelet at the upper end of the spring bar for passing through and deflecting a warp tape 3. The warp-tape guide elements 2 are arranged around the circular reed 4 of the circular weaving machine 1 in a distributed fashion. The circular reed 4 comprises an upper collar 4a and a lower collar 4b between which a plurality of reed bars 4c with clearances 4d between adjacent reed bars 4c are arranged in an equally distributed fashion. The warp tapes 3 are passed through the warp-tape guide elements 2 by warp-tape bobbin, which are not illustrated, and are passed along through the clearances 4d between the reed bars 4c.

(6) Between the warp-tape guide elements 2 and the circular reed 4, shed forming devices 5 are arranged around the circular reed 4 in a distributed fashion. The shed forming devices 5 comprise a plurality of first laces 6 and a plurality of second laces 7, which are interconnected at their ends and entwine an upper roll 8a as well as a lower roll 8b. Each of the first laces 6 has an eyelet 6a through which a warp tape 3 is guided. Said warp tapes passed through the eyelets 6a of the first laces 6 form a first warp-tape group 10. Each of the second laces 7 has an eyelet 7a through which a warp tape 3 is guided. Said warp tapes passed through the eyelets 7a of the second laces 7 form a second warp-tape group 11. At least one of the upper roll 8a and/or the lower roll 8b is rotated alternately into a first and an opposite second direction of rotation, whereby the laces 6, 7 entwining them are moved upwards and downwards in an alternating manner. As a result, a mutually opposed upward and, respectively, downward alternating movement is imparted to the two warp-tape groups 10, 11, with the result that the weaving shed 9 (also referred to as a moving shed) is opened and closed. In the opened state, the weaving shed 9 forms a space defined by the two warp-tape groups 10, 11, in which a weaving shuttle 12 carrying a weft-tape bobbin 13 moves on an orbit along the circular reed 4 and, in the process, draws off a weft tape, which is not illustrated, from the weft-tape bobbin 13 it carries, introducing it into the weaving shed 9. The weaving shed 9 is closed if the laces 6, 7 are located in a central position in which the eyelets 6a, 7a of the first laces 6 and the second laces 7 are on the same level, whereby both warp-tape groups 10, 11 are located in the same surface 9a or, respectively, jointly span said surface 9a. In other words, the surface 9a of the closed weaving shed 9 is the angle bisector between the first warp-tape group 10, which, in FIG. 1, is the upper warp-tape group, and the second warp-tape group 11, which, in FIG. 2, is the lower warp-tape group. It thus holds true that the angle 1 between the first warp-tape group 10 and the surface 9a is equivalent to the angle 2 between the second warp-tape group 10 and the surface 9a. At the same time, the surface 9a is defined as the surface containing the geometric connecting lines between the warp-tape guide elements 2 and the weaving ring 15.

(7) The size of the space of the weaving shed 9 as defined by the two warp-tape groups 10, 11 changes constantly with the opposing movement of the two warp-tape groups 10, 11, starting from zero with a closed weaving shed. The space of the weaving shed 9 reaches a maximum if the two warp-tape groups 10, 11 are located at the opposite reversal points of their opposing alternating movement, as illustrated in FIG. 1. At those reversal points, the so-called shed change starts by reversing the movement imparted to the opposed warp-tape groups 10, 11. Due to the shed change, the weft tape introduced last into the weaving shed 9 is fixed in the fabric and the next weft tape can be introduced into the weaving shed by the next shuttle 12. As can be seen in FIG. 2, several weaving shuttles 12 circulate in the circular reed 4 at equal distances from each other. The produced tubular fabric 14 is guided inwards toward a centrally arranged weaving ring 15, where it is deflected toward drawing-off rolls 16.

(8) According to the invention, the weaving shuttle 12 keeps the bobbin axis 13a of the weft-tape bobbin 13 at an angular position which deviates by at most +/15, preferably at most +/10, from a normal to the surface 9a of the closed weaving shed 9, using a bobbin holding device 12b. In the embodiment of the circular weaving machine according to FIG. 1, the weaving shuttle 12 keeps the bobbin axis 13a of the weft-tape bobbin 13 at right angles to the surface 9a of the closed weaving shed 9. The surface 9a of the closed weaving shed 9 forms a circular ring surface.

(9) The circular weaving machine 1 is designed for the use of plastic tapes as warp tapes and weft tapes, the plastic tapes being elongated for achieving a higher strength. In order that the advantages of the circular weaving machine according to the invention are brought to bear fully, a type of weft-tape bobbin is used which is modified in comparison to conventional weft-tape bobbin in that the bobbin length L is reduced and the bobbin diameter D is increased. In the full condition of the weft-tape bobbin 13, the bobbin diameter D thereof is larger than the bobbin length L, whereby the available space in the weaving shed 9 can be utilized optimally. Because of this bobbin form, the weaving shuttle 12 can be constructed shorter, resulting in a reduction in its mass. As with the recommended bobbin form, the bobbin core 13b can be shorter and thus lighter, also the weft-tape bobbin 13 is lighter. The respective weight reductions of the bobbin 13 and of the weaving shuttle 12 result in a significant reduction in the centrifugal force acting on the supporting rolls 12a, the circular reed 4 and other structural elements during the rotation of the weaving shuttles 12.

(10) Due to the suggested bobbin form, it is possible to reduce the required shed travel, resulting in a shortening of the reed bars 4c. In contrast to longer reed bars, shorter reed bars 4c will produce less noise caused by vibrations of the bars. A further noise reduction can be achieved by reducing the number of revolutions and the lower rotational speed of the weaving shuttles 12. A further advantage of the new bobbin form, in comparison to long bobbin of small diameters, is the lesser volume loss via the bobbin core relative to the total volume of the bobbin.

(11) Because of the higher weft count of the described circular weaving machine 1, a smaller number of looms are required for the same output of fabric, which reduces the required space at the manufacturing facilities.

(12) The following table shows a comparison of relevant technical data of a conventional type FX circular weaving machine of the applicant to those of the circular weaving machine according to the invention.

(13) TABLE-US-00001 prior art invention Weft count [picks per <1200 ppm >1200 ppm minute] No. of shuttles 6 10 Shuttle weight >5 kg <3 kg Centrifugal force 1300 N 300 N Shed travel 160 mm 100 mm Compensation distance >13 mm <4 mm

(14) FIG. 3 schematically shows a side view of a second embodiment of a circular weaving machine 1 according to the invention. Said second embodiment of the circular weaving machine 1 differs from the first embodiment shown in FIGS. 1 and 2 only in that the weaving ring 15 is positioned higher than the warp-tape guide elements 2, whereby the course of the first warp-tape group 10 and the second warp-tape group 11 is inclined obliquely upwards toward the central machine axis 17. For this reason, the weaving shed 9 is also inclined accordingly. The result is that the surface 9a of the closed weaving shed 9 forms a truncated cone surface with the machine axis 17 as the truncated cone axis. In this exemplary embodiment, also the circular reed 4 is designed as an upwardly expanding truncated cone. The remaining components of the circular weaving machine 1 in the second embodiment thereof correspond to those of the first embodiment and are indicated by the same reference characters. As for a description of those components, reference is made to the above explanations.