TWISTER DEVICE WITH ROTARY SPIRAL FOR A WINDING CARRIAGE

Abstract: A twister device with mobile spiral (3) for a winding carriage for collecting sliver (9) onto cross-wound bobbins (16) and arranged to insert a false twist into said sliver leaving a gill box (2) or derived machine. Said device comprises at least one rotary spiral element (3) coupled to undergo horizontal to-and-fro movement integrally with a rotary funnel-type false twist element (6), this latter being of the known art. The rotary spiral element (3) is disposed upstream of the rotary funnel-type element (6), ie it precedes this latter in twisting the sliver being collected. The two elements cooperate to wind a compact and rounded sliver on the collection bobbin, which must assume a geometrically correct shape, and also cooperate in elastically compensating the sliver, which must never be subjected to false draft during the winding traversing motion.

Description: This invention relates to a twister device with mobile spiral element for inserting a false twist into a sliver leaving a gill box or derived machine. In the description given hereinafter and in the claims the term "sliver" will be used throughout to indicate a textile fibre roving, a textile fibre sliver or any other aggregate of textile fibres. In a gill box with sliver collection on bobbins of conventional type, the package is built up by winding the sliver on an idle roller, rotated by one or more fluted rollers, by means of a false twist device arranged to give the sliver roundness and strength and to allow individuality in subsequent unwinding. To allow a cross-wound sliver bobbin to be formed, the false twist device is driven reciprocatingly along a path of travel equal substantially to the desired length of the bobbin. It is well known that the conveying of the sliver between the exit calender unit of the gill box and the winding system must be as constant as possible, not only to allow formation of a uniform winding but also to take account of the fact that the sliver is often fragile, as its constituent fibres are short or held together with little twist. Winding must therefore be carried out very uniformly and with the fibres as condensed as possible so that the cohesion between the fibres does not allow false draft to arise in that part of the sliver between its exit from the gill box and its entry into the yarn guide element or into the rotating funnel of the false twist element. The sliver must be subjected to the collection tension essential for the formation of a compact bobbin, but said tension must remain sufficiently constant not to change the dimensional and quality characteristics of the sliver between the exit of the calender unit and the point at which the winding operation is carried out. Relatively large tension variations could also lead to sliver breakage. It is also clear that a breakage of this kind interrupts the production process and requires the assistance of service personnel. The labour cost of such ergency assistance is a considerable factor in calculating the production costs. Various solutions have already been proposed to overcome this winding problem. In US-A-3,670,978 it is proposed for example to pass the sliver through an intermediate guide ring mounted between the exit of the gill box calender unit and the winding system in a manner mobile such that the sum of the distance between the ring and the calender exit and the distance between the ring and the sliver guide is always constant. Different systems based on the same principle have also been proposed and constructed, comprising for example toggle joint levers or similar elements able to form the desired linkage. However, these solutions all have draw-. backs in that they involve the reciprocating movement of relatively large masses, and cannot be applied to current high-speed machines, not only because of the large amount of energy involved and the rapid wear of the various members, but also because vibration and consequent fatigue failure can occur. Many attempts have been made by the applicant to ensure a sliver bobbin winding which is as uniform as possible. A typical example of these practical attempts by the applicant is decribed in EP-A-0 295 731 (prior art document according to Article 54(3) EPC) which discloses a twister device with a mobile spiral element for a winding carriage for collecting a sliver onto cross-wound bobbins, wherein said mobile spiral element is coupled to an active twisting unit to undergo reciprocating to-and-fro movement integrally with a rotary funnel-type false twist element, arranged within said active twisting unit and wherein said mobile spiral element being disposed upstream of the false twist element, the two elements cooperating to wind a compacted and rounded sliver on the collection bobbin and to keep said sliver always subject to elastic compensation during its periodical variation between the intermediate collection points and the end collection points on said forming bobbin. Said device works well compared with devices already proposed in the art, however its operation could be improved. In this repect, the application of said previously proposed device has been found not perfectly satisfactory in that when certain types of sliver are used it results in non-uniform twisting because of the intricate guiding of the sliver along the fixed turns of the spiral element. This effect, even if very limited, is undesirable because it ruins the appearance of the sliver and in addition can initiate false draft which influences the strength of the collected sliver during its unwinding in the next processing stage. In the light of this and of the aforesaid defects and drawbacks, the object of the present invention is to provide an improved twister device of the last mentioned type, which is able to compensate the variation in distance between a fixed feed outlet and a mobile sliver guide subjected to to-and-fro movement, so as to obtain a collected sliver which is compact and round without suffering the aforesaid drawbacks. To this end, according to the invention, a twister device is proposed having the features as defined in claim 1. Further preferred features of the twister device according to the invention are defined in the subclaims. The rotary spiral element can be constructed of steel spring wire or another wear-resistant material. Said wire is wound in a substantially cylindrical shape with a pitch, diameter and number of turns dependent on the material to be worked. As it consists merely of a steel wire, the rotary spiral element according to the invention has minimum inertia and offers no substantial hindrance to the reciprocating movement of the overall twister device. The rotary spiral element therefore acts essentially as a compensator for compensating the length differences and at the sliver entry end is of flattened form to guide the sliver, whereas at its exit end it is fixed to the rotary funnel-type twist element. The rotary spiral inserts a large number of twists into the sliver to give that bond and compactness to the fibres required to make the sliver totally elastic under the tensioning action during cross-winding. In this respect, the rotary spiral element inserts in the sliver both a twist deriving from its spiral part and a twist deriving from its rotation. More specifically, the purpose of the rotary spiral element is to guide the sliver at the entry to the rotary funnel-type element while simultaneously giving the sliver a consistent number of twists which extend towards the calender unit and also implements the initial compacting and rounding stage prior to its entry into said rotary funnel-type false twist element. The twists inserted into the sliver leaving the calender rolls by the rotary spiral element advantageously bind together the component fibres of the sliver, to enable it to be tensioned by elastic elongation, to perfectly compensate the distance variation without the danger of creating false draft. By virtue of this particular combination and arrangement, the compensation and twist insertion are provided by simple means, and the lightness of the rotary spiral element results in the collection rate in the machine being substantially increased. The combination of the rotary spiral element and the funnel-type false twist element is overall fairly light in weight, adaptable to the various machine types and considerably economical. Said combination enables very fragile slivers consisting for example of short fibres with poor adhesion to be worked, and in such cases enables breakages and continuity interruptions in the fibre aggregate to be prevented, and also prevents the fibres sliding on each other resulting in changes in cross-section which impair the sliver quality. A preferred embodiment of the device of the present invention is described hereinafter by way of non-limiting example with reference to the single accompanying drawing, together with clarification of further constructional details and characteristics. The accompanying drawing shows a diagrammatic side view of a twister and compensator device according to the invention cooperating upstream with the calender rolls through which the sliver leaves the gill box and cooperating downstream with the cross-winding system for forming the sliver collection bobbin. On the drawing: 2 is a dashed line schematically indicating the gill box or derived machine; 1 is the calender unit operating as a feed means for the sliver leaving the gill box 2; 7 is the presser roll of the calender unit 1, which together with the roll 8 continuously extracts the fibre sliver 9 from the drafting zone; 9 is the textile fibre sliver consisting substantially of a more or less numerous aggregate of textile fibres of varying length; 10 is a ring with a lateral slot advantageously arranged for inserting the sliver 9. Said ring is profiled internally with an annular surface of spherical profile converging in the feed direction of the sliver 9, which is guided into the rotary spiral element 3; 3 is a rotary spiral element, in the form of a helical spring with one or more helixes, of positive inner diameter and with a turn pitch depending on the spinning machine and the material to be worked. Said spiral element 3 has two ends, one of which is joined to the guide ring 10 and the other is fixed to the ring 11; 11 is a ring which enables the rotary spiral element 3 to either be rigidly fixed to the rotary funnel-type element 6; 6 is the rotary funnel-type element for inserting the false twist necessary to give the sliver 9 roundness and strength before its collection on the periphery of the forming bobbin 16: 19 is the plate for connecting and supporting the device of the present invention to and on the reciprocating winding carriage 20 which is guided to move parallel to the axis of the forming bobbin 16; 24 is the bush slidable along the cylindrical guide bar 22 positioned parallel to the axis 30 of the drive roller 32 for the forming bobbin 16; 26 is the profiled support plate for the entire device, and driven with reciprocating motion along a transverse travel path substantially equal to the desired axial length of the bobbin 16; 4 is the bearing assembly allowing the rotary funnel-type element 6 to rotate about itself while caused by the reciprocating winding carriage 20 to continuously move to-and-fro; 5 is the non-rotating outer casing of the rotary funnel-type element 6; 18 is the suitably shaped grooved pulley which by the action of a round belt 12 or similar element and with the cooperation of the backing surface or guide 15 generates the rotary movement of the element 6 by deriving it from said reciprocating movement; 14 is the condensing bush with an inner surface of spherical, conical or frusto-conical profile converging in the direction along which the sliver 9 is collected on the bobbin 16. The operating description given hereinafter with reference to the said figure relates in particular to the twister device according to the invention, whereas those elements or devices which are cooperative or complementary during operation are not described, as these are of the known art. The sliver, roving or fibre aggregate leaving the calender unit 1 is inserted into the guide ring 10 through the lateral slot and is conveyed through the rotary spiral element 3 and into the rotary funnel-type element 6 to be collected on the surface of the bobbin 16 rotating on the winding spindle 28. The twist inserted both by the rotation of the spiral element 3 and by the friction along the inner surface of its helix turns travels back rapidly and continuously as far as the rolls 7 and 8 to give, the sliver that torsional compactness necessary to make it elastic under the alternate tensioning present in a cross-winding. A preferred embodiment of the invention has been described herein, but modifications are possible: ther shape and relationship of the parts can be changed, the wire of the spiral element can be other than circular in shape, such as oval, rectangular or the like, the fixing elements 11 and 19 can be shaped and mounted differently, without leaving the scope of the present invention as claimed hereinafter.

Claims: A twister device with a mobile spiral element (3) for a winding carriage (19-20) for collecting a sliver (9) onto cross-wound bobbins (16), wherein said spiral element (3) is coupled, to undergo reciprocating to-and-fro movement, to an active false twist unit (5) comprising a rotary funnel-type false twist element (6) to which said spiral element (3) is rigidly fixed and wherein said spiral element (3) is deposed upstream of the funnel-type false twist element (6), the two elements (3,6) cooperating to wind a compacted and rounded sliver (9) on the bobbin (16) and to keep said sliver (9) always subjected to elastic compensation during its periodical variation between the intermediate collection points and the end collection points on said forming bobbin (16). A device as claimed in claim 1, characterised in that said rotary spiral element (3) has the main purpose to induce in the sliver (9) the twist necessary for elastically compensating, during winding, the periodical distance variation between the fixed gill box calender (1) exit point and the mobile yarn guide which undergoes continuous to-and-fro movement. A device as claimed in claim 1, characterised in that the rotary spiral element (3) is formed with its inner diameter of substantially constant positive value along the axis of the helix, said value depending on the thickness and type of fibre of the sliver (9) to be worked. A device as claimed in claim 1, characterised in that the rotary spiral element (3) has one end fixed to the rotary funnel-type false twist element (6) and its other end fixed to guide ring (10) for the sliver (9) originating from the gill box calender unit (1).

Inventors: SARTONI, SANDRO
Applicants: SAVIO S.P.A.
Application year: 1988
Main classification: B65H59
IPC codes: D01H7, D01H1