"Lap forming device for a lap-winder"

[0001] The present invention relates to a lap forming device for machines processing a fibre web, such as a lap-winder.

[0002] A fibre processing line involves processing of the fibre, usually starting from the fibre in flock to obtain a yarn.

[0003] The system is composed of numerous machines; in particular, the carding machines permit a fibre web to be obtained .

[0004] In a lap-winder positioned downline of the carding machines, a plurality of webs are drawn and wound to form a web wound on a tube to form a lap in a lap forming device.

[0005] One embodiment example of a lap forming device is described in the International Application

PCT/IB2010/052766, in the Applicant's name.

[0006] The laps are then sent to combing machines and the web produced by these starting from the laps is sent to the drawing frames, fly frames and spinning units to form webs, reels of roving and yarn respectively.

[0007] It is extremely important to produce regular laps without fraying while limiting machining times, so as to increase the productivity of the system. [0008] The purpose of the present invention is to make a lap forming device, in particular for a lap winder, able to speed up the lap formation cycle while maintaining in any case the quality of the lap obtained.

[0009] Such purpose is achieved by a lap forming device made according to claim 1.

[0010] The characteristics and advantages of the forming device according to the present invention will be evident from the description given below.

[0011] Figures 1 to 12 show a sequence of the lap forming cycle by a lap forming device according to the present invention .

[0012] Figure 13 shows an example of embodiment of means of loading the tubes of the lap forming device.

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

[0014] The device 1 has an input area 2 for the input of a web W, coming from machines upstream of the device 1, such as drawing and winding equipment of the lap winder.

[0015] Preferably, the device 1 comprises a feed unit 4 to receive and deviate the incoming web W according to an input direction IN.

[0016] The lap L is formed by the web W wound around a tube T, preferably perforated on its surface. [0017] The device 1 further comprises a pair of calenders, at least one of which is motorised, preferably with a fixed rotation axis, for the formation of the lap L. On start-up of the lap forming cycle, the tube T is placed on the two calenders.

[0018] In particular the device 1 comprises a primary calender 22, having a primary diameter Dp, and a secondary calender 24, having a secondary diameter Ds . Preferably, the primary diameter Dp is smaller than the secondary diameter Ds .

[0019] Preferably, in addition, the device 1 comprises an auxiliary belt 38 which forms a closed circuit and is at least partially wound around the primary calender 22, remaining in contact with the tube T and then with the lap being formed.

[0020] According to a preferred embodiment, in addition, the lap forming device 1 further comprises a mobile chute 30, for example which can be rotated, for example in the form of a plate, on which the web W moves, positioned downstream of the feed unit 4 and upstream of the primary calender 22.

[0021] The mobile chute 30 is therefore suitable to occupy an active position, in which it assumes an inclination such as to point to the area included between the two calenders 22, 24, and an inactive position, rotated in relation to the active position, in which it points outside the area between the two calenders 22, 24.

[0022] The device 1 further comprises drive means suitable to axially limit the movement of the lap L being formed or of the tube.

[0023] For example, said drive means comprise a carriage 40 comprising a pair of plates 42, positioned distanced along the rotation axis of the calenders 22, 24 so as to define an area between them.

[0024] The plates 42 can translate along a rectilinear carriage axis Y, generally inclined from the vertical, to follow the tube being wound.

[0025] Preferably, in addition, the plates 42 comprise suction means suitable to interact with the tube T supported by the calenders 22, 24 to create a vacuum on its surface.

[0026] The carriage 40 is thus able to pass from an initial configuration wherein the plates are in a limit lowered position wherein the centring means are at the minimum distance from the calenders, to a final configuration in which the plates are translated along the carriage axis Y from the limit lowered position, and occupy a limit raised position wherein the centring means are at the maximum distance from the calenders,

[0027] Furthermore, preferably, the device 1 comprises loading means able to load an empty tube T between the calenders 22, 24.

[0028] For example, said loading means comprise a loading arm 50 suitable to receive an empty tube T, movable between a loading position, in which the tube can be loaded onto the arm, and an unloading position, in which the tube rolls between the calenders; for example, the arm 50 can be rotated between said positions.

[0029] According to a preferred embodiment, the loading means further comprise a tube feed unit 100 suitable to feed empty tubes to the loading arm 50 (figure 13) .

[0030] The tube feed unit 100 is axially alongside the lap forming device and comprises a column frame 102 in which the empty tubes are piled (generally manually loaded from above into the column frame by means of an inclined plane 103 placed at a predefined height along the column frame) and a mobile partition system which by opening and closing alternately enables the descent of a single empty tube at a time into a pre-loading area 106 on the bottom of the column frame 102.

[0031] In addition, the unit 100 comprises drive means of the pre-loaded tube, for example comprising a pneumatic cylinder 108 which moves a translating arm 110 which pushes the empty tube from the pre-loading area 106 onto the loading arm 50. [0032] The feed unit 4 preferably comprises a plurality of drive cylinders, between the lateral surfaces of which passages are formed defining a feed path for the web W.

[0033] In particular the feed unit 4 comprises a first lower cylinder 62 and a second lower cylinder 64, the second downline of the first, and a first 66, second 68 and third 70 upper cylinder, one downstream of the other.

[0034] The upper cylinders 66, 68, 70 are positioned around the first lower cylinder 62, so that the web W is positioned partially around the first lower cylinder 62; in particular, the third upper cylinder 70 engages the first 62 and the second 64 lower cylinder, so as to deviate the path of the web W from the first lower cylinder 62.

[0035] In addition, the feed unit 4 comprises drive means suitable to command a cylinder or calender to move in rotation .

[0036] For example, said drive means comprise at least one electric motor.

[0037] Preferably, at least one of said drive cylinders is connected to said drive means.

[0038] Preferably, in addition, the forming device comprises speed adjustment means able to influence the drive means to selectively impose at least one low speed and at least one high speed to the organs influenced by said drive means, that is the cylinders or calenders.

[0039] In addition, the feed unit 4 comprises a lower output cylinder 72 and an upper output cylinder 74, which can be engaged for example pressure engaged by means of the web W in transit between them.

[0040] In particular the output cylinders 72, 74 have rotation axes which can be brought closer together or further apart to pressure engage or disengage said cylinders to/from each other by means of the web W between them.

[0041] In particular preferably, the lower output cylinder 72 has a fixed rotation axis, while the upper output cylinder can be brought further away or closer to the lower cylinder 72, so as to be pulled or not in rotation by the web in transit between them.

[0042] In addition, the feed unit 4 comprises coupling means suitable for coupling kinematically upon command at least one of said output cylinders 72, 74 with said drive means, to place it in controlled rotation.

[0043] Preferably, in addition, the feed unit 4 comprises further coupling means for engaging/disengaging the drive means from the drive cylinders 62-70.

[0044] The feed unit 4 further comprises, preferably, brake means, activated on command, to block the rotation of at least one of said output cylinders 72, 74. [0045] Preferably, the brake means are activated and keep the lower output cylinder 72 blocked while the upper cylinder 74 is dragged by contact when engaged to the lower cylinder 72.

[0046] The lap forming device 1 is suitable to perform a forming cycle to form the lap L.

[0047] According to a first step of the cycle (figure 1), the device 1 is in an initial configuration in which the tube T is loaded on the arm 50, positioned in the loading position, the carriage is in the initial configuration, the mobile chute is in the passive position and the web W is positioned between the drive cylinders and the output cylinders, projecting with its head downstream of these.

[0048] The brake means are activated and keep the lower output cylinder 72 blocked.

[0049] Subsequently, the arm 50 rotates to the unloading position (figure 2) and the empty tube 2 rolls between the calenders 22, 24; subsequently again, the arm 50 returns to the loading position and remains there until the subsequent cycle (figure 3).

[0050] According to a subsequent step of the cycle (figure 4), the mobile chute rotates to an active position and the calenders rotate at a low speed, making the tube T rotate .

[0051] Subsequently the drive cylinders 62-70 rotate; at the same time the brake means are disactivated (so the lower output cylinder is therefore free to rotate) and the coupling means are activated, placing the lower output cylinder 72 in rotation (figure 5).

[0052] The web W then begins to move on the mobile chute 30 towards the web forming area, between the two calenders 22, 24.

[0053] The suction means are also activated, to create a vacuum through the holes present on the surface of the tube T, to attract the web W to the tube T (figure 6) .

[0054] According to a subsequent step of the cycle (figure 7), the web W begins to wind onto the tube T at low speed and the plates 42 progressively translate along the carriage axis Y, to accompany the lap L being formed.

[0055] Subsequently, the mobile chute 30 returns to the inactive position, the upper output cylinder 74 goes into the position of disengagement from the lower cylinder 72, the coupling means are disactivated and the brake means activated, blocking the lower cylinder 72 (figure 8).

[0056] According to a subsequent step of the cycle (figure 9) , the calenders 22, 24 and the drive cylinders 62-70 are placed in rotation at high speed to form the lap L quickly.

[0057] The lap is therefore formed with the lower cylinder 72 immobile, that is braked, and the upper cylinder 74 raised from the lower cylinder 72, that is detached so as not to feel the influence of the lap in transit.

[0058] The formation of the lap L at speed continues until a length (or weight) of wound lap close to the final desired length is reached (figure 10) .

[0059] According to a subsequent step of the cycle (figure 11), the rotation speed of the calenders 22, 24 and of the drive cylinders 62-70 is low and the upper output cylinder 74 returns to the engaged position, in which it is dragged in rotation by the moving web W.

[0060] For example, the speed reduction takes place when about 3 metres of web W are missing for completion of the lap L .

[0061] According to a subsequent step of the cycle (figure 12), when the final length of wound web W is reached, the drive means are disconnected from the drive cylinders 62- 70 (for example by further coupling means), thereby stopping formation of the lap L.

[0062] The secondary calender 24 is controlled in slow rotation so that the web is torn downstream of the output cylinders 72, 74 pinched together.

[0063] Lastly, the plates 42 raise the lap L formed and release it so that it rolls beyond the secondary calender 24.

[0064] After loading a new empty tube T onto the arm 50, the formation cycle recommences from the first step shown .

[0065] Innovatively, the forming device according to the present invention makes it possible to form the laps quickly.

[0066] Advantageously, during the formation step the web runs over the lower cylinder blocked in rotation so that the fibres composing the web are smoothed before winding; this considerably improves the quality of the wound web, in that it tends to significantly diminish the hairiness of the web.

[0067] In addition, advantageously, in the start-up phase, during which the lower cylinder is controlled in rotation and the upper cylinder pinches the web onto it, the web is effectively driven downstream of the pinching area, towards the calenders, while upstream of the pinching area it remains taut.

[0068] According to a further advantageous aspect, in the final step of the cycle when the web is torn, the lower cylinder 72 is blocked and the upper cylinder 74 pinches the web onto it, so that the tearing of the web occurs regularly and always downstream of the pinching area.

[0069] It is clear that a person skilled in the art may make modifications to the forming device described above so as to satisfy contingent requirements while remaining within the sphere of protection of the following claims.