"LAP FORMING DEVICE FOR A LAP-WINDING MACHINE"

[0001] The subject of the present invention is a forming device of a lap for machines for processing fibre tapes, such as a lap-winder.

[0002] A fibre processing system provides for processing the fibre, generally starting with fibre flakes, to obtain a thread.

[0003] The system comprises numerous machines. While carding machines enable the production of fibre tapes, in a lap-winder, installed after the carding machines, a plurality of tapes are wound and joined together, forming a web, then wound onto a tube to form a lap in a formation device.

[0004] Examples of devices for the formation of ^' the lap are described in the International Applications WO 2011/077267, WO 2011/073831, WO 2012/011055, in the Applicant's name.

[0005] The laps are then sent to the combers and the tape made by them starting from the laps is sent to the winders, roving frames and spinning frames, for the formations of tapes, roving and thread reels respectively .

[0006] It is very important to produce regular laps, containing working time, in order to increase system productivity .

[0007] The purpose of the resent invention is to make forming device of the lap, particularly for a lap-winder, capable of preserving the regularity of the form of the laps.

[0008] Said purpose is achieved by a forming device for the lap made in accordance with claim 1.

[0009] The characteristics and advantages of the forming device according to the present invention will, be evident in the following description, provided by way of non- limiting example in accordance with the annexed figures, in which:

[0010] figure 1 shows a diagram of a forming device of the lap for a lap-winder, according to the present invention, in accordance with a preferred embodiment;

[0011] - figures 2 to 5 show a sequence of the work phases of the forming device of the lap; and

[0012] - figure 6 shows a diagram of a pneumatic circuit of the forming device of the lap.

[0013] According to the invention, a machine for preparing for spinning, for processing fibre tapes or a web for example, such as a lap-winder, comprises a forming device 1 of the lap.

[0014] The device 1 presents an en entrance area 2 for the entrance of a web W, coming from apparatus before the device 1, such as the drawing and joining apparatus of the lap-winder.

[0015] Preferably, the device 1 comprises a feeding group 4 to receive the incoming web W following an entrance direction IN and the deviation.

[0016] For example, the feeding group 4 comprises a plurality of guide cylinders, such as a lower cylinder 4a and an upper cylinder 4a, between the lateral surfaces of which passages are created to define a feeding path for the web W.

[0017] The lap L is formed by the web W wound around a tube T, preferably with a perforated surface.

[0018] The device 1 also consists of a pair of calenders, motorised for example, preferably with a fixed rotation axis, for forming the lap L. When the web forming cycles starts the tube T rests against the two calenders.

[0019] In particular, the device 1 consists of a primary calender 22, with a primary diameter Dp, and of a secondary calender 24, with a secondary diameter Ds . Preferably, the primary diameter Dp is smaller than the secondary diameter Ds .

[0020] Also preferably, the device 1 consists of an auxiliary belt 40 which forms a closed circuit and is at least partially wound around the primary calender 22, keeping in contact with the tube T and then with the lap being formed.

[0021] The device 1 also consists of the guide means to guide the winding of the web around the tube.

[0022] Said guide means consist of a carriage 41 fitted with a couple of plates 42 spaced along the rotation axis of the calenders 22, 24 in order to delimit a zone between them.

[0023] The plates 41 are translatable along a straight carriage axis Y, generally inclined with respect to the vertical, to follow and guide the lap being formed.

[0024] Preferably, the carriage comprises centring means provided on the plates 42, to keep the tube in a set position in relation to said plates; the plates 42 generally consist in round discs and said centring mean define a tube axis coinciding with the central axis of said plates.

[0025] Also preferably, the plates 42 consist of suction means suitable for interacting with the tube T supported by the calenders 22, 24 to create a depression on its surface.

[0026] The carriage 41 is therefore suitable for passing from an initial configuration, in which the plates are in a lowered limit position, to a final configuration, in which the plates are translated along the carriage axis Y with respect to the lowered limit position, and occupy a raised limit position.

[0027] Also, the forming device 1 consists of loading means for the lap suitable for keeping the lap being formed in forced contact with the two calenders, in order to increase the compacting of the web being wound around the tube .

[0028] According to a preferred embodiment, said loading means consist of two piston-cylinder groups 50, each one connected to the respective plate 42, suitable for influencing the plates towards the lowered limit position during the formation of the lap, also allowing the raising of the plates, so that the winding of the web to the tube is very compact.

[0029] According to the variant shown, the piston-cylinder groups 50 are suitable for pulling the plates towards the lowered limit position during the formation of the lap.

[0030] Also, the device 1 consists of unloading means suitable for keeping the lap L being formed suspended above the calenders 22, 24 during a pause in formation of the lap.

[0031] According to a preferred embodiment, said unloading means also consist of the two dual effect piston-cylinder groups 50, powered to influence the plates towards the raised limit position, in order to keep the lap being formed suspended above the calenders. [0032] According to the variant shown, the piston-cylinder groups 50 are suitable for pushing the plates towards the raised limit position during the pause in formation of the lap.

[0033] The forming device 1 comprises a preferably pneumatic actuation circuit 60, for the controlled power supply of the piston-cylinder groups 50.

[0034]· The actuation circuit 60 comprises a valve 62, a solenoid valve for example, for the power supply of the two piston-cylinder groups 50 as loading means or alternatively unloading means.

[0035] For example, said valve is a bistable valve, with two working positions A, B and a central rest position C.

[0036] In the first working position A, the loading means are actuated, meaning that the two piston-cylinder groups are powered to push the lap towards the calenders; in the second working position B, the unloading means are actuated, meaning that the two piston-cylinder groups are powered to overcome the weight of the lap and the carriage and keep the lap suspended above the calenders.

[0037] The forming device 1 also comprises control means suitable for actuating the loading means and the unloading means according to need.

[0038] Preferably, the control means detect a machine stop signal during the formation of the lap and command the unloading means through an unloading actuation signal. Also, the control means detect a go signal during the formation of the lap and command the loading means through a loading actuation signal.

[0039] Also preferably, the control means comprise a timer suitable for determining the duration of actuation of the unloading means; also preferably, said timer is suitable for sending a timing signal variable according to the state of forming of the lap, so that, particularly, the actuation interval of the unloading means is longer the further the forming of the lap is advanced.

[0040] In other words, the piston-cylinder groups, during the raising of the lap, operate for an interval of time that is longer the further the forming of the lap is advanced and therefore the higher it is raised above the calenders. Therefore, near the end of the formation of the lap, it will be considerably raised, while near the start of formation, it will be less raised.

[0041] The forming device 1 is suitable for performing a forming cycle for the formation of the lap L.

[0042] In accordance with an initial phase of the cycle (figure 2) , the device 1 is in an initial configuration in which the tube T is supported by the two calenders 22, 24, the carriage is in the initial configuration, the suction means are activated to create a depression through the holes on the surface of the tube T, to attract the web W to the tube T and the web W starts to wind around the tube T.

[0043] In accordance with the forming phase of the lap (figure 3), the web W keeps winding around the tube and the plates 42 gradually translate along the carriage axis Y, to accompany the lap L being formed.

[0044] During the forming phase, the lap loading means are activated. In other words, the lap is influenced towards the calenders, or pushed towards the calenders by the cylinder groups 50, so that the web is wound compactly. The valve 62 is active in the first working position A.

[0045] Before the lap forming is completed, the machine might stop, due to the breakage of the web being wound for example.

[0046] In these conditions (figure 4), the loading means are deactivated and the loading means are activated, so that the weight of the carriage and their own weight do not deform the lap.

[0047] In other words, the piston-cylinder groups 50 invert their action and carry the lap so that it suspended above the calenders, overcoming the weight of the lap and the carriage. The valve 62 is active in the second working position B.

[0048] After the stop, the unloading means are deactivated and the loading means are reactivated (figure 5), so that the lap rests again and is forced against the calenders 22, 24, and the forming of the lap. starts again, until the length of web wound (or a weight) close to the final length desired is reached.

[0049] Innovatively, the forming device according to the present inventions makes it possible to obtain very regular shaped laps, in that it prevents deformation due to the stoppage of the machine.

[0050] In fact, in traditional machines, the stop causes the lap to oval, due to its own weight and the weight of the carriage which hangs from said lap, supported by the calenders.

[0051] It is clear that a technician in the field, in order to satisfy contingent requirements, could make alterations to the forming device, described above, all contained within the scope of defence as defined in the following claims.