Textile machine

Abstract: In order to control cotton fibre fluctuation between the compactor device (5) and the drafting unit (6) within a card (1A), the drafting unit (6) can be moved (either along a rectilinear trajectory and/or along a circular trajectory) between a first position (L) coinciding with its maximum distance from the compactor device (5) and a second position coinciding with its minimum distance from said compactor device (5) until said distance is reduced to the minimum possible. The distance between the drafting unit (6) and the compactor device (5) varies in a manner inversely proportional to the operating speed of the card (1A). In an alternative embodiment: a support and guide element (40) for the web (9) is positioned between the doffer (2) and the pair of rollers (7, 8) of the compactor device (5); a conveyor device (24) is interposed between the compactor device (5) and the drafting unit (6).

Description: This invention relates to a textile machine in accordance with the classifying part of claim 1. During the processing of textile fibres and in particular cotton fibres by carders, the problem arises of controlling the fibre fluctuation which occurs in the processed product (web) mainly in the section between the compactor device and the drafting unit. A constant final product quality depends on constant fluctuation intensity. The patents US-A-3,925,850 and DE-A-36 17 525 describe devices which substantially suggest solving the aforesaid technical problem by measuring at the conveyor device (in the form of a funnel of fixed convergence) the density of the web produced by the card and on the basis of this density controlling the card operating parameters (roller rotational speed) to achieve the desired density. The patents DE-A-27 32 016 and CH-A-575 479 describe devices which substantially suggest solving the aforesaid technical problem by providing downstream of the roller compactor device a conveyor device the convergence of which can be varied. The conveyor devices described in the two documents differ from each other mainly by the manner of forming the elements which enable the convergence to be varied. Finally US-A-5,018,248, which represents the closest prior art suggests solving the aforesaid technical problem by measuring the thickness of the fibre sliver downstream of a conveyor device by a suitable device interposed between said conveyor device and the drafting device, and consequently acting on the operating parameters. From the examined state of the art it can be essentially seen that: the existence of various technical solutions involving operating on said web when this lies between the conveyor device and the drafting device shows that the treatment and hence behaviour of the web fibres during passage from the doffer to the drafting device is very important for the final product quality; the technical problem has not yet been solved satisfactorily in all its aspects, and subsequently the currently proposed solutions are susceptible to improvement. The object of the present invention is therefore to provide a textile machine, particularly but not exclusively for processing cotton, which is improved such as to solve the aforesaid problem in a particularly effective and hence satisfactory manner and which is also substantially economical. This object is attained by a textile machine in accordance with claim 1, to which reference should be made for brevity. The solution is new because in no document of the state of the art is it suggested to reduce to a minimum (and possibly to zero) the gap between the doffer and the drafting device as the operating speed of the machine is increased. The solution is inventive because whereas all devices involve merely acting on the fibres within the gap between the conveyor device and the drafting device, the invention substantially reduces (possibly to zero) said gap on the basis of the operating speed, hence eliminating all fluctuation at its origin and consequently eliminating any problem occurring within said gap or in the web lying therein. The teaching on which the invention is based is therefore exactly contrary to that on which the aforesaid known art is based, because whereas this latter is directed to finding solutions based on better handling of said web portion, the invention essentially teaches to progressively reduce and possibly eliminate the web portion between the doffer and the drafting unit, and consequently the relative fibre fluctuation. The invention is illustrated by way of non-limiting example with reference to a cotton carder which currently appears to be the machine which mostly benefits from the invention, but without excluding its application to other fibres and to other textile machines provided with drafting devices such as drawing frames, spinning machines and the like. The invention is illustrated by way of non-limiting example in the figures of the accompanying drawings. Figure 1 is a schematic side view of a first embodiment of the textile machine according to the invention. Figure 2 is a schematic side view of a second embodiment of the textile machine according to the invention. Figure 3 is a plan view from above of the machine of Figure 2. Figure 4 is a frontal view of the first and second embodiments of the machine shown in Figures 1 and 2, illustrating a first method of driving the drafting unit. Figure 5 is a frontal view of the first and second embodiments of the machine shown in Figures 1 and 2, illustrating a second method of driving the drafting unit. Figure 6 is a schematic side view of a third embodiment of the textile machine according to the invention. Figure 7 is a schematic side view of a fourth embodiment of the textile machine according to the invention. Figure 8 is a frontal view of the third and fourth embodiments of the machine, shown in Figures 6 and 7. Figure 9 is a schematic side view of a fifth embodiment of the textile machine according to the invention. With particular reference to Figures 1, 4 and 5, the textile machine of the invention, indicated overall by 1A, is a card for processing cotton fibres. It comprises a detachment roller 2, commonly known as a doffer roller, a brush device 3, a stripper roller 4, a compactor device 5 and a drafting device 6. The compactor device 5 comprises in the illustrated embodiment a first roller 7 and a second roller 8 of different diameters. The web 9 detached from the doffer roller 2 along its entire width by the stripper roller 4 passes between said rollers 7 and 8. The drafting device 6 comprises at least two pairs (a first 10 and a second 11) of superposed presser rollers, at least one of said pair being motorized by at least one electric motor 12. Figure 4 shows the motor 12, which by means of the first belt 13 drives the lower roller 17 of the second pair 11, and by means of the second belt 18 drives the lower roller 15 of the first pair 10. The lower rollers 15 and 17 of each pair are knurled parallel to their axes. The drafting device 6 comprises presser elements 19 (mounted on a cover 34 hinged at 35) acting elastically on the axles of the idle upper rollers 14 and 16 of each pair 10, 11, which are consequently pressed into contact with the motorized lower rollers 15, 17. The illustrated drafting device 6 also comprises an intake element 20 for the web 9 which is preferably in the form of a funnel. The drafting device 6 can be positioned between a first position of maximum withdrawal (indicated by the dashed and dotted line L in Figure 1) and a second position of maximum approach (shown by full lines in Figure 1) by translational movement along a trajectory which in the illustrated embodiment is rectilinear and parallel to the axis along which the web 9 moves between the compactor device 5 and the drafting unit 6. The means for translationally moving the drafting device along a rectilinear trajectory comprise at least one pair of rectilinear guides 21 rigid with the drafting unit 6 and slidable, under the action of at least one hydraulic actuator 23, parallel to the axis of movement of the web 9 on bushes 22 fixed to the card frame. The movement means can be controlled by a computer on the basis of operating parameters well known to the expert of the art. Of these, the most important is the rotational speed of the textile machine rollers. Briefly, during the operation of the card 1A the drafting device 6 is positionable between a first position L coinciding with maximum distance from the compactor device and a second position coinciding with minimum distance from said compactor device 5, said second position possibly being such as to reduce said distance from the compactor device 5 to the minimum possible. The distance between the drafting device 6 and the compactor device 5 is varied in a manner inversely proportional mainly to the operating speed of the textile machine. This variation could also be decided on the basis of numerous other card operating parameters, not stated herein as they are well known to the expert of the art. In this latter case the positioning of the drafting device is particularly advantageous if also effected during machine operation, and could be made automatic if controlled by a computer (not shown). By operating in this manner the cotton fibre fluctuation between the compactor device 5 and the drafting unit 6 is controlled in an optimum manner during card operation, so eliminating the problems which could derive therefrom by virtue of the fact that the length of web between the device 5 and the drafting unit is so reduced (if not actually nullified) as to be of no influence. With particular reference to Figures 2, 3, 4 and 5, the textile machine of the invention, indicated overall by 1B, is a cotton fibre processing card which differs from that shown in Figure 1 by the fact that between the compactor device 5 and the drafting unit 6 there is interposed a conveyor device 24 for the web 9. In the illustrated embodiment, the conveyor device 24 is of the type comprising at least two opposing annular belts 25 each of which moves about rollers 26 having their axis 27 incident or rather substantiall perpendicular to the doffer roller 2. The annular belts 25 form an exit gap 28 for the web 9 which converges within said exit gap 28. The presence of the conveyor device 24 for the web 9 increases the effectiveness of the invention in that the fibres of the web 9 are better regularized and stabilized. With particular reference to Figures 6 and 8, the textile machine of the invention, indicated overall by 1C, is a cotton fibre processing card which differs from that shown in Figure 1 by the fact that the drafting unit 6 is positionable between the first position H and the second position by moving along a circular trajectory. It can be seen from the drawings that although of equal effectiveness its structure is simpler than that of the preceding embodiments. The means for moving the drafting unit 6 along a circular trajectory comprise at least one first hinge 29 (a pair thereof in the illustrated embodiment) securing the drafting device 6 to the base of the machine 1C, at least one second hinge 30 securing the drafting unit 6 to the rod 31 of at least one second hydraulic actuator 32, and at least one third hinge 33 securing said second hydraulic actuator 32 to the base of the machine 1C. With particular reference to Figures 7 and 8, the textile machine of the invention, indicated overall by 1D, is a cotton fibre processing card which differs from that shown in Figure 6 by the fact that between the compactor device 5 and the drafting unit 6 there is provided a conveyor device 24 for the web 9. Again in this case the conveyor device 24 is preferably of the type comprising at least two opposing annular belts 25 each of which moves about rollers 26 having their axis 27 substantially perpendicular to the doffer roller 2. The web conveyor device 24 offers the advantages already indicated for the embodiment of Figure 2. With particular reference to Figure 9, according to the fifth embodiment, the machine of the invention, indicated overall by 1E, comprises between the doffer 2 and the pair of rollers 7 and 8 of the compactor device 5 a web support and guide element 40 which has given excellent experimental results. The support and guide element 40 extends substantially along the entire width of the doffer roller 2 and stripper roller 4. Figure 9 clearly shows the cross-sectional shape of the support and guide element 40 and its position relative to said doffer roller 2 and stripper roller 4. The support and guide element 40 is applicable to any of the textile machines of the present invention. In a sixth embodiment of the textile machine (not shown), the drafting unit 6 moves along a trajectory obtained by combining a rectilinear translational movement with a barycentric rotation.

Claims: A textile machine (1A-1E) of the type comprising at least one doffer (2) and at least one drafting unit (6) positioned downstream of said doffer (2) with respect to the direction of advancement of the product textile fibre web (9) characterized in that the drafting unit (6) is positionable between a first position (L) coinciding with its maximum distance from the doffer (2) and a second position coinciding with its minimum distance from said doffer (2), said second position possibly being such as to reduce said distance from the doffer (2) to the minimum possible, the distance between the drafting unit (6) and the doffer (2) varying in a manner inversely proportional to the operating speed of the textile machine (1A-1E). A machine as claimed in claim 1, characterised in that a support and guide element (40) for the web (9) is positioned between the doffer (2) and the pair of rollers (7 and 8) of the compactor device (5). A machine as claimed in claim 1, characterised in that the drafting unit (6) is positionable between the first position (L) and the second position by translational movement along a rectilinear trajectory. A machine as claimed in claim 3, characterised in that the means for translationally moving the drafting unit (6) along a rectilinear trajectory comprise at least one pair of rectilinear guides (21) rigid with the drafting unit (6) and slidable parallel to the axis of movement of the web (9) on bushes 22, under the action of at least one first hydraulic actuator (23). A machine as claimed in claim 1, characterised in that the drafting device (6) is positionable between the first position (H) and the second position by translational movement along a circular trajectory. A machine as claimed in claim 1, characterised in that in a sixth embodiment of the textile machine, the drafting unit (6) is movable along a trajectory obtained by combining a rectilinear translational movement with a barycentric rotation. A machine as claimed in claim 5, characterised in that the means for translationally moving the drafting device along a circular trajectory comprise at least one first hinge (29) securing the drafting unit (6) to the machine base, at least one second hinge (30) securing the drafting unit (6) to the rod (31) of at least one second hydraulic actuator (32), and at least one third hinge (33) securing said second hydraulic actuator (32) to the machine base. A machine as claimed in claims 3 and 4, characterised in that the drafting unit (6) can also be positioned during machine operation and is controlled by a computer. A machine as claimed in one or more of the preceding claims, characterised in that between the compactor device (5) and the drafting unit (6) there is provided for the web (9) a conveyor device (24) comprising at least two opposing annular belts (25), each of which moves about rollers (26) having their axis (27) incident to the doffer roller (2), with convergent movement within an exit gap (28). A machine as claimed in claim 1, characterised by being a cotton processing card. A machine as claimed in claim 1, characterised in that the drafting unit (6) comprises at least two pairs (10, 11) of superposed presser rollers (14-17), at least one of said pairs being motorized by at least one electric motor (12). A machine as claimed in claim 11, characterised in that the lower rollers (15, 17) of each pair (10, 11) are knurled parallel to their axis. A machine as claimed in claim 11 or 12, characterised in that the drafting unit (6) comprises presser elements (19) acting elastically on the axles of the idle upper rollers (14, 16) of each pair (10, 11), which are consequently pressed elastically into contact with the motorized lower rollers (15, 17). A machine as claimed in claim 11, 12 or 13, characterised in that the drafting unit (6) comprises an intake element (20) of funnel form. A method for controlling the fibre fluctuation of a textile fibre web (9) travelling between the compactor device (5) and a drafting unit (6) within a card (1A-1D), characterised by varying the length of that web portion (9) between the compactor device (5) and the drafting unit (6) in inverse proportion to the machine operating speed. A method as claimed in claim 15, characterised in that the length of that web portion (9) between the compactor device (5) and the drafting unit (6) is varied by varying the position of the drafting unit (6) relative to the compactor device (5). A method as claimed in claim 16, characterised in that the length of that web portion (9) between the compactor device (5) and the drafting unit (6) can also be varied during the operation of the textile machine (1A-1D).

Inventors: COSSANDI ANTONIO, PASINI GIOVANNI BATTISTA, PATELLI SILVANO, COSSANDI, ANTONIO, PASINI, GIOVANNI BATTISTA, PATELLI, SILVANO
Applicants: MARZOLI SPA, MARZOLI S.P.A.
Application year: 1996
Main classification: D01G15
IPC codes: D01G15