"Lap winding device for a textile machine, for example a lap-winder, provided with an auxiliary belt".

[001] The present invention relates to a lap-winding device for machines processing fibre webs, such as a lap- winder .

[002] A fibre processing system envisages processing of the fibre, usually starting from fibre flocks, to obtain a yarn.

[003] The system is composed of numerous machines; in particular, the carding machines enable a fibre web to be produced .

[004] In a lap-winder, positioned downstream of the carding machines, a plurality of webs are wound and joined together, to form a web, wound on a tube to form a- lap .

[005] One embodiment of a lap-winding device is described in EP-A1-1464739, in the name of the Applicant. Further examples are described in EP 160165 and US 3134553.

[006] The laps are then sent to the combing machines and the web produced by these starting from the laps is sent to the lap-winders, roving frames and spinning frames, for the formation of webs, reels of roving and yarn respectively. [007] It is extremely important to produce regular laps without fraying.

[008] However, the laps are formed, in the devices of the known art, by remaining in contact under pressure with two calenders rotating at high speed. The lap, formed by winding a soft web, especially near the point of initial contact with the primary calender, tends to form a thickening, caused by the resistance of the web being wound against the surface of the first calender. This phenomenon is known in the field as "thickening".

[009] The purpose of the present invention is to make a lap-winding device, in particular for a lap-winder, able to overcome or limit the problem of formation of the thickening .

[0010] Such purpose is achieved by a lap-winding device made according to claim 1 below. The dependent claims describe embodiment variations.

[0011] The characteristics and advantages of the lap- winding device according to the present invention will be evident from the description given below.

[0012] The attached figures 1 to 8 shows diagrams of a lap-winding system according to the present -invention, according to different embodiments.

[0013] According to the invention, a machine for processing fibre webs or a lap, such as a. lap-winder, comprises a lap-winding device 1.

[0014] The device 1 has an input area 2 for the input of a web W, coming from machinery upstream of the device 1, for example from winding and joining equipment of the lap-winder.

[0015] Preferably, the device 1 comprises an input group 4 for receipt of the incoming web W in an input direction IN and deviation of the direction of advancement, positioned in the entrance area 2.

[0016] For example, the input group 4 comprises an input cylinder 6, generally motorised, and at least one input roller, generally idler, positioned around the input cylinder 6 to engage the web W. For example, three input rollers are provided 8a, 8b, 8c, around the input cylinder 6 and act in conjunction with it to drag the web W. Moreover, the input group 4 comprises an alignment roller 12, which the web W passes over before continuing towards a forming area 20 of a lap L.

[0017] According to a preferred embodiment (figures 7 and 8), the input group 4 comprises a pair of output cylinders 12a, 12b, at least one of which motorised, pressure coupled for the transit of the web W between them.

[0018] The lap L is formed by the web W wound around a tube T perforated on the surface. [0019] The device 1 comprises, in addition, a pair of calenders, for example motorised, preferably with a fixed rotation axis, for the formation of the lap L. When the formation cycle of the lap is started, the tube T rests on the two calenders, in contact with the surface of the same in respective contact areas.

[0020] In particular, the device 1 comprises a primary calender 22, rotating around an axis 22', which with the tube T, when this is resting on the primary calender 22, forms a primary contact axis 22a; the primary calender has a primary diameter Dp; the primary diameter Dp defines a primary cylindrical surface 22b of the primary calender 22.

[0021] The web W, coming out of the alignment roller 12 or from the pair of output cylinders 12a, 12b, is directed towards the primary contact axis 22a.

[0022] In the same way, the device 1 comprises a secondary calender 24, rotating around an axis 24', which with the tube T, when this is resting on the secondary calender 24, forms a secondary contact axis 24a; the secondary calender has a secondary diameter Ds; the secondary diameter Ds defines a secondary cylindrical surface 24b of the secondary calender 24.

[0023] When the lap forming cycle is started, the web W, reaching the secondary contact axis 24a with its tip for the first time, already has a section wound onto the tube T, in that the winding began at the primary contact axis 22a.

[0024] According to one embodiment (figure 1), the primary contact axis 22a is misaligned between the primary calender 22 and the tube T in relation to the alignment roller 12, and, specifically, is rearward of it.

[0025] From a geometric point of view, between the rotation axis 22' of the primary calender 22 and the axis Ί" of the tube T, a primary reference plane I' is defined; the primary reference plane I' intersects the primary contact axis 22a; an initial web plane Wi is also defined, tangent to the alignment roller 12 and passing through the primary contact axis 22a.

[0026] Given the previous definitions, the primary contact axis 22a between the primary calender 22 and the tube T is misaligned in relation to the alignment roller 12 in the sense that the initial web plane Wi is inclined in relation to the primary reference plane I ¹ , in other words is not orthogonal to it.

[0027] According to a further embodiment, the primary contact axis 22a between the primary calender 22 and the tube T is rearward of the alignment roller 12 in the sense that the initial web plane Wi forms an acute angle with the primary reference plane I ¹ on the side of the tube T, in other words an obtuse angle on the -side of the primary calender 22. That is to say, the initial web plane Wi intersects the tube T.

[0028] According to yet a further embodiment, the initial web plane Wi forms an angle with the primary reference plane I', of 0° to 89°, for example 45° to 85°, for example 55° to 75°, preferably 60° to 65°.

[0029] Advantageously, such arrangement makes it possible to wind the web onto the tube T or to the lap being formed in a joining area upstream of the primary contact axis 22a. It has been found that such aspect considerably facilitates the formation cycle, significantly limiting the thickening phenomenon, since the web is already wound and joined to the lap when it reaches the area of the primary contact axis 22a, where it encounters strong pressure from the calender.

[0030] According to one embodiment variation, by moving the primary contact plane 22a further back from the alignment roller 12, the initial web plane Wi forms a negative angle with the primary reference plane .1 ¹ . For example, the initial web plane Wi forms an angle with the primary reference plane I' of -15° to 0°, for example of -5°.

[0031] According to a further embodiment, the forming area 20 is asymmetric, in that the primary diameter Dp of the primary calender 22 is a different length from the secondary diameter Ds of the secondary calender (figures 3, 7 or 8), or the distancing of the web being formed from the calenders is not symmetrical but inclines towards the secondary calender (figure 2) .

[0032] Advantageously, such characteristics make it possible to distribute the excess pressure in the primary and secondary contact areas asymmetrically, facilitating formation of the lap.

[0033] From a geometric point of view, a calender axes plane A ¹ is defined as the plane containing the two axes 22', 24' of the two calenders 22, 24; a reference plane I' is defined as the plane containing the rotation axis 22' of the primary calender 22 and the axis Ί" of the tube T; the reference plane I'' is defined as the plane containing the rotation axis 24' of the secondary calender 24 and the axis T' of the tube T; the median plane M is defined as the plane bisecting the angle 22'- T'-24'.

[0034] From further geometrical constructions (figure 2) it has been verified that the axis T' of the tube, during formation of the lap, moves on a plane of the centres Ί" ' which, given the asymmetry, does not coincide with the median plane M. [ 0035] According to the variation in which the primary diameter Dp is greater than the secondary diameter Ds

(figure 2), the plane of the centres Ί" ' is inclined, in the forming area 20, so as to be closer to the primary calender 22 in relation to the median plane M.

[ 0036] It is believed that the increase in over pressure in the primary contact area 22a derives from this .

[ 0037 ] According to a preferred embodiment the primary diameter Dp is less than the secondary diameter Ds (figures 3, 7 and 8), and, in particular, the ratio of the primary diameter Dp to the primary calender 22 and the secondary diameter Ds of the secondary calender 24 is 0.1 to 0.4, preferably 0.15 to 0.3, preferably equal to 0.23 or 0.27 (figures 3, 7 and 8).

[ 0038 ] In such preferred embodiment, the plane of the centres T' ¹ is inclined, in the forming area 20, so as to be further from the primary calender 22 in relation to the median plane M. It is believed that the reduction in over pressure in the primary contact area 22a derives from this.

[ 0039 ] According to one embodiment, the plane of the centres T ^{1 1} forms, with the median plane , an angle of 5° to 20°, preferably 10° to 15°, preferably equal to 12° or 13° or 14° on the side of the secondary calender. [0040] Preferably, the device 1 comprises an auxiliary belt 40 which forms a closed circuit and is at least partially wound on the primary calender 22, remaining in contact with the tube T and then with the lap being formed (figures 7 and 8) .

[0041] In such embodiments, the device 1 comprises a pair of return rollers 50a, 50b, positioned rearwards of the primary calender 22, on the side opposite the forming area 20.

[0042] The auxiliary belt 40 winds onto the primary calender 22 and onto the two return rollers 50a, 50b, forming the closed circuit.

[0043] According to a preferred embodiment, the lap- winding device 1 comprises a mobile guide 30, for example rotatable, for example in the form of a plate, which the web W moves on.

[0044] According to one embodiment, the mobile guide 30 is positioned downstream of the pair of input cylinders 12a, 12b and upstream of the primary calender 22 (figures 7 and 8) .

[0045] Preferably, moreover, the device 1 comprises a fixed guide 60, for example in the form of a plate, positioned between the input cylinder 6 and the pair of output cylinders 12a, 12b.

[0046] According to a further embodiment, the mobile guide 30 is positioned downstream of the alignment roller 12 and upstream of the primary calender 22, which the web moves on (figures 3, 4 and 6) .

[0047] Preferably, the guide 30 is movable from an active position, in which it guides the web W especially when starting the formation cycle, towards the tube T, and a rest position, in which it is distanced from the primary calender, so as not to interfere with the lap being formed.

[0048] According to a further embodiment (figure 4), the lap-winding device 1 has the primary contact axis 22a between the primary calender 22 and the tube T rearwards of the alignment roller 12 and the asymmetric forming area 20, as well as the mobile guide 30.

[0049] Preferably, moreover, the device 1 comprises suction means 32, joined to the mobile guide 30, to hold the web W, especially during the initial phase of the formation cycle.

[0050] According to a further embodiment, at least some of the components of the device 1 in contact with the web in the forming area 20 of the lap comprise air current evacuation means.

[0051] For example, the primary calender 22, which is in contact with the web W in the forming area 20, has a surface provided with holes (figure 5), from which the currents of air forming in the forming area of the lap, can escape, to reduce their disturbing effect on the web.

[0052] According to a further example, air aspiration devices are provided in the forming area 20 to aspirate the currents of air formed.

[0053] According to yet . a further example, the mobile 30 guide, at least near the forming area 20, has holes for the escape of the currents of air (figure 6) .

[0054] In yet a _. further variation, the _. lap-winding device 1 comprises said evacuation devices, the asymmetric forming area and the rearward primary contact area .

[0055] The device 1 comprises, in addition, guide means for guiding the lap being formed or the tube.

[0056] For example, said guide means comprise a carriage comprising a pair of plates, positioned distanced along the rotation axis of the calenders 22, 24, so as to define an area between them.

[0057] The tube T, still without the web wound around it, when formation of the lap is started, rests on the two calenders 22, 24 and is positioned between the plates 52 of the guide means.

[0058] The carriage comprises, in addition, first movement devices, connected to the plates, for the movement of the same in a direction of formation, for example coinciding with the direction tangent to the two calenders 22, 24.

[0059] For example, said movement devices are pneumatic.

[0060] During normal functioning of the lap-winding device 1, in an initial configuration of formation of the lap, the tube T rests on the calenders 22, 24, without the web W.

[0061] Preferably, in the embodiment provided with an auxiliary belt 40 wound on a section of the primary calender 22, the tube T is in contact with the auxiliary belt 40 at said sectio in contact with the surface of the primary calender 22.

[0062] The carriage is in a retracted limit position, and the two ^"" plates are at the axial ends of the tube T, containing it .

[0063] During normal functioning of the lap-winding device 1, the calenders 22, 24 are placed in rotation, the web W is fed to the input group 4 and deviated towards the tube T.

[0064] The rotation of the tube T and of the calenders 22, 24, assisted if necessary by the negative pressure generated inside the perforated tube T, permits winding of the web W onto the tube T. [0065] In an intermediate formation configuration, the lap is pressed by the carriage onto the two calenders 22, 24 in rotation and fed with the web W.

[0066] The carriage is in an intermediate position, in which the plates are translated along the direction of formation, distanced from the rotation axes of the calenders 22, 24 by a greater distance than in the initial formation configuration.

[0067] In a final formation configuration, the lap has the desired maximum volume, the carriage is in the forward limit position, that is the axes of the plates are at the maximum distance from the rotation axes of the calenders.

[0068] According to yet a further embodiment, the device 1 comprises tube centring devices, for example comprising a pair of truncated cone-shaped inserts, attached centrally to the plates, suitable for being inserted in the tube T, so as to centre its position, at least upon starting of the formation cycle of the lap.

[0069] Innovatively, the lap-winding device according to the present invention makes it possible to eliminate or reduce thickening during the formation of the lap.

[0070] Advantageously, moreover, the device makes it possible to use high rotation speeds for the formation of the lap, while maintaining high quality standards. [0071] It is clear that a person skilled in the art may make modifications to the lap-winding device described above so as to satisfy contingent requirements.

[0072] According to one embodiment variation, the primary calender is idler.

[0073] According to a further variation, the primary calender is motorised.

[0074] According to yet a further variation, the secondary calender is- motorised independently of the primary calender.

[0075] Such variations too are contained within the sphere of protection as defined by the following claims.