CH714998B1 - Method of working a combing head of a combing machine. - Google Patents

Abstract

A method of working a combing head of a combing machine which comprises the steps of detaching a tuft (S ') from a combed strip by means of a pair of detachment rollers in continuous rotation, transferring the tuft ( S ') to auxiliary rollers (20a, 20b), send the tuft (S') through the auxiliary rollers (20a, 20b) to a main roller (30) having a peripheral speed lower than the peripheral speed (Vd) of the rollers auxiliaries, collide the tuft (S ') against the main roller (30) and pull it from there so that a head section of the tuft (S') is arranged on the main surface (28) and directed towards an exit passage (32), while a tail section of the tuft is arranged on the auxiliary device, form a loop between the head section and the tail section of the tuft, detach an additional tuft (S ' '), send said additional tuft (S' ') to the main roller (30) so that a sectio n of the head of the additional tuft (S '') crosses the tail section of the tuft (S '), form a continuous combed strip, take the combed strip out of the outlet passage (32) and transfer the combed strip to a transfer device (40) so that, on the transfer device (40), the cross section of the additional tuft (S '') is placed under the tail section of the tuft (S ').

Description

Field of the invention

The present invention relates to a working method of a combing head of a combing machine of a spinning preparation line.

In a spinning preparation line, after the first steps of opening and cleaning the fiber, carding is carried out by carding machines, after which the fiber is in the form of a ribbon. .

After a possible treatment on a ribbon gatherer, according to which several separate ribbons are assembled to obtain a web, the strip or the ribbon is combed by a combing machine in order to obtain a ribbon in which the fibers are highly parallelized and clean.

Prior art

The basic combing operations, which in more recent machines follow one another at the rate of 500 to 550 strokes per minute, consist of: feed the tape intermittently; comb, by means of a rotary comb, the head of the incoming tuft, with the pliers closed; overlap and connect the tuft head to the strip already combed during the previous cycle, suitably moved backwards, by means of detachment rollers when they rotate backwards; comb the tail of the tuft using a straight pliers comb, with open pliers; advance the combed tuft by the detachment rollers during their forward rotation.

The detachment rollers therefore have an alternating rotational movement. The moving parts of the detachment rollers, which, from an electric motor, control the detachment rollers and allow reciprocating movement, constitute one of the most problematic parts of the design and manufacture of a comb.

These elements must indeed withstand intense dynamic stresses, because they are subjected to repeated stops and restarts. When the speed of the machine increases, the speed of rotation increases proportionally in one direction and in the other of the detachment rollers. Dynamic constraints are therefore becoming increasingly heavy.

These elements also have a large size and represent at least 30% to 40% of the final cost of the combing machine.

There are patents illustrating combing machine solutions with a unidirectional rotational movement of the detachment rollers. Consider, for example, document EP-A1-1553219.

However, the applicant, reproducing for experimental purposes the solution illustrated in document EP-A1-1553219, was able to note that the result of the combing is not satisfactory from the point of view of the quality of the ribbon obtained.

Another embodiment of a combing machine with detaching rollers with unidirectional movement is described in Italian patent application No. 102018000001987, in the name of the applicant.

Finally, there are other combing machine solutions in which the detachment rollers are controlled by an electric motor controlled electronically to obtain the reciprocating rotational movement; in this case, the complicated mechanical movement elements of said detachment rollers are not necessary.

However, these solutions have considerable drawbacks, mainly related to energy consumption, the heating of electric motors, the duration of these motors and the response of the motion control.

Purpose of the invention

The object of the present invention is to propose a working method for a combing head of a combing machine with detachment rollers having a continuous rotational movement (at constant or variable speed, but unidirectional), which is capable of ensuring a satisfactory quality level of the combed tape.

Such an object is achieved by a working method of a combing head according to claim 1 or 3. The dependent claims describe other advantageous embodiments of the invention.

Description of the figures

The characteristics and advantages of the working method of a combing head according to the present invention will appear more clearly on reading the description which follows, produced by way of indicative and nonlimiting example with reference to the drawings annexed, on which: FIG. 1 schematically represents a combing head of a combing machine, used according to an embodiment of the present invention; Figures 2 to 10 schematically show working steps of the combing head according to the present invention; Figures 11 to 15 show other embodiments of the combing head used according to the present invention.

Detailed description of the invention

First embodiment (Figures 1 to 10)

A combing machine used according to this embodiment comprises a fixed frame and a plurality of combing heads, each combing head comprising a clamp 4 carried by the fixed frame.

The clamp 4 includes a lower jaw 6, an upper jaw 8 and a straight comb 10, generally in one piece with the lower jaw 6.

In addition, the clamp 4 includes a feed roller 12, which can be rotated on command intermittently, carried by the lower jaw 6.

The combing head further comprises, downstream of the clamp 4, at least one pair of detachment rollers.

For example, preferably immediately downstream of the clamp 4, in front of it, is a pair 20 'of detachment rollers 20a', 20b ', superimposed, preferably in pressure contact, provided with a continuous rotational movement (at constant or variable speed, but not invertible), for example to pull a piece of strip protruding from the jaws, detach a tuft from the strip and bring it downstream.

According to this embodiment, downstream of the pair 20 'of detachment rollers 20a', 20b 'is a pair 20 of auxiliary rollers, comprising an upper auxiliary roller 20a and a lower auxiliary roller 20b, generally coupled by pressure on the upper auxiliary roller 20a and preferably driven in rotation by the latter.

Between the auxiliary rollers 20a, 20b, on the upstream side, having defined an imaginary entry plane P1 tangent to the two auxiliary rollers 20a, 20b, an entry orifice 22 is identified between said entry plane P1 and the lateral surfaces of the auxiliary rollers 20a, 20b. On the opposite side, that is to say on the downstream side, having defined in the same way an outlet plane P2, an outlet orifice 24 is identified instead.

The auxiliary rollers 20a, 20b have a continuous rotational movement (at constant or variable speed but not reversible), so as to pull a section of strip supplied by the detachment rollers 20a ', 20b', to detach a tuft tape and bring it from the inlet port 22 to the outlet port 24.

Said auxiliary rollers 20a, 20b have the same peripheral speed Vd and respective angular speeds Wa, Wb.

Furthermore, the combing head comprises a main device 26, placed in front of the outlet orifice 24 of the auxiliary rollers 20a, 20b, provided with a movable main surface 28, for example in translation, against which, and in particular against an impact zone 29 of said main surface 28, a tuft emerging from the auxiliary rollers 20a, 20b collides.

The main surface 28 is provided with a main speed Va, in particular in the impact zone 29.

For example, said main device 26 comprises a main roller 30, provided with a continuous rotational movement (at constant or variable speed, but in all cases unidirectional), clockwise or in the opposite direction, arranged downstream of the auxiliary rollers 20a, 20b, in front of them, facing the outlet orifice 24.

The main roller 30 has a lateral surface 30 'which constitutes said main surface 28 of the main device 26.

The side surface 30 ', that is to say the main surface 28, is airtight. In other words, no hole or suction opening is provided on said surface.

The main roller 30 generally has a diameter greater than the diameter of the main detachment rollers 20a, 20b and a peripheral speed Vm, which corresponds to an angular speed Wm.

The peripheral speed Vm of the main roller 30 is lower than the peripheral speed Vs of the auxiliary rollers 20a, 20b.

For example, the peripheral speed Vm of the main roller is between 20 - 40% of the peripheral speed Vs of the auxiliary rollers, for example between 25 - 35%, for example between 28 and 32%, for example around 30 %.

Preferably, a third imaginary plane P3 having been defined, tangent to the auxiliary rollers 20a, 20b and passing through the contact line between them, the axis of rotation 30 '' of the main roller 30 is disposed au- above or above the third plane P3, as a function of the main speed Va, that is to say of the direction of rotation of the main roller 30 opposite the outlet orifice 24.

For example, in the representation of Figure 2, the direction of rotation of the main roller 30 opposite the outlet orifice 24 is downwards and the axis of rotation 30 '' of said main roller 30 is located below the third plane P3.

In other words, the third plane P3 defines a direction of exit of the tufts S 'from the exit orifice 24.

The combing head further comprises a transfer device 40 on which, as will be seen below, a tuft of tape is brought, which leaves the main surface 28 of the main device 26, or the lateral surface 30 ' said main roller 30; said tuft moves in a transfer zone 42 of said transfer device 40.

Preferably, the transfer device 40 is engaged with the main surface 28 of the main device 26; for example, said transfer device 40 is tangent to the lateral surface 30 'of said main roller 30 along a line of engagement L.

Preferably, said transfer device 40 is flat in the vicinity of said engagement line L.

In addition, preferably, said transfer zone 42 of the transfer device 40 is flat.

After defining a lower plane of the imaginary centers P4 passing through the axis of rotation of the lower auxiliary roller 20b and the main roller 30, said lower plane of the centers P4 intersects the side surfaces of the lower auxiliary roller 20b and the main roller 30, by defining a lower passage 32 traversed by the tuft which is detached from the main surface 28, that is to say from the lateral surface 30 ′, to move on the transfer device 40.

An imaginary upper plane of the centers P5 is also defined, passing through the axis of rotation of the upper auxiliary roller 20a and the main roller 30; said upper plane of the centers P5 intersects the lateral surfaces of the upper auxiliary roller 20a and of the main roller 30, by defining an upper passage 34.

The lower passage 32, through which the tuft detached from the main surface 28, that is to say from the lateral surface 30 ', passes in order to move towards the transfer device 40, is narrower than the upper passage 34.

In other words, the tuft which is detached from the main surface 28, that is to say from the lateral surface 30 ', to move towards the transfer device 40 passes through the narrower passage (passage defined output) between the two passages made by the lower auxiliary roller 20b and the upper auxiliary roller 20a relative to the main surface 28 of the main device 26, namely the lateral surface 30 '.

The transfer area 42 is located in front of the lower passage 32, for example upstream of the engagement line L, with reference to the direction of the main speed Va or of the peripheral speed Vm of the main roller 30 in said engagement line L.

In addition, preferably, said transfer device 40 is mobile, that is to say provided with a predefined support speed Vs in the engagement zone 42.

For example, the combing machine is provided with a conveyor belt 50 which performs a closed loop trajectory, preferably outside the main roller 30, and which forms, for at least part, said device. transfer 40.

The speed of the belt 50 in the engagement zone 42 corresponds to said support speed Vs and is a function of the main speed Va or the peripheral speed of the main roller 30 in the engagement line L.

For example, in the engagement line L, the belt 50 is tangent to the main surface 28 or to the lateral surface 30 'of the main roller 30.

Preferably, the belt 50, in order to define its own closed loop trajectory, is wound around at least one deflection roller, preferably a pair 60 of deflection rollers 60a, 60b, for example arranged under the auxiliary rollers 20a, 20b, and around an additional roller 60c, preferably arranged downstream of the main roller 30.

Preferably, the combing head further comprises a pair 70 of pressure rollers 70a, 70b, coupled by pressure, between which the combed strip W carried by the transfer device 40 passes to flatten and regularize the thickness.

Preferably, at least one 70b of said pressure rollers 70a, 70b coincides with the additional roller 60c on which the belt 50 is wound.

In addition, preferably, the combing head comprises a pair 80 of end rollers 80a, 80b, coupled by pressure, between which the strip W passes, preferably after having been flattened and regularized, to exit the combing area and after deviating from its own trajectory.

Preferably, at least one 80b of said end rollers 80a, 80b coincides with the additional roller 60c on which the belt 50 is wound.

Finally, according to the illustrated embodiment, the pressure roller 70a and the end roller 80a are external to the path of the belt 50 and are coupled by pressure to the additional roller 60c on which said belt 50 is wound, by defining together a curved trajectory.

The combing head further comprises a circular comb 90, generally arranged below the clamp 4, provided with a continuous rotational movement, at a constant or variable speed, always in the same direction.

The combing machine is provided with one or more electric motors and a plurality of transmission elements adapted to transfer the movement of said at least one electric motor to the components mentioned above.

In particular, the clamp has a forward and backward movement and the jaws have an opening and closing movement with a predefined working speed.

In addition, the clamp 4 is provided with a reciprocating movement of advance and retreat between an advanced limit position, in which the jaws 6, 8 are proximal to the detachment rollers 20a ', 20b' and a rear limit position, in which said jaws 6, 8 are distal with respect to said detachment rollers 20a ', 20b'.

At the same time, the jaws 6, 8 are provided with an alternating opening and closing movement, while the feed roller 12 is provided with an intermittent rotational movement which allows a strip section to be released from the clamp.

When the clamp is in the advanced limit position, a combing sector of the circular comb combs the head of the strip section projecting from the jaws and said head is taken between the detachment rollers 20a ', 20b', causing tearing a tuft S ', which is transported from upstream to downstream by the rotation of the rollers 20a', 20b 'and transferred to the auxiliary rollers 20a, 20b (Figure 2).

For the tuft S ', a head section Hs' and a tail section Ts' are defined. The tail section Ts 'of the tuft S' is combed by the straight comb 10.

The continuous rotation of the auxiliary rollers 20a, 20b with the speed Vd causes the tuft S 'to advance from the inlet orifice 22 to the outlet orifice 24, until the head section H 'collides against the main surface 28 of the main device 26 or against the lateral surface 30' of the main roller 30 (Figure 3).

Due to the relationship between the peripheral speed Vd of the detachment rollers 20a, 20b, on which depends the mode with which the tuft S 'collides against the main surface 28, and the main speed Va, the head section Hs 'of the tuft S' is arranged on the main surface 28 or on the lateral surface 30 'of the main roller 30, and is directed towards the narrowest passage, that is to say the lower passage 32, while the tail section Ts' is disposed on the side surface of the upper auxiliary roller 20a. Between the head section Hs' and the tail section Ts', a loop R 'is formed between the upper auxiliary roller 20a and the main roller 30, i.e. on the side of the wider passage, this is ie overpass 34 (Figure 4).

Gradually, from the head section to the tail section, the tuft S 'moves on the main surface 28 of the main device 26 or on the lateral surface 30' of the main roller 30 (FIG. 5), and is thus transported.

During traction, the tuft S 'is not subjected to any current of suction air which makes it adhere to the main surface 28.

The head section Hs' of the tuft S 'begins to detach from the main surface 28 or the lateral surface 30' of the main roller 30, passing through the lower passage 32 and moving towards the area of transfer 42 of the transfer device 40 (Figure 6).

Gradually, the tuft S 'with the head section Hs' collides against the transfer device 40 and gradually the tail section Ts 'is detached from the main surface 28 or the lateral surface 30' of the main roller 30, while an additional tuft S '' is transferred to the auxiliary rollers 20a, 20b by the detachment rollers 20a ', 20b' (Figure 7).

The additional tuft S '' has a respective head section Hs '' and a respective tail section Ts ''. During this time, the head section Hs 'of the tuft S' is driven by the transfer device 40.

Like the tuft S ', the head section Hs'' of the additional tuft S '' is directed towards the main device 26, that is to say towards the main roller 30, colliding against the tail section Ts 'of the tuft S' (Figure 8). The head section Hs 'of the tuft S' continues to be driven by the transfer device 40.

The head section Hs '' of the additional tuft S '' crosses the tail section Ts 'of the tuft S', by an overlapping section S * (FIG. 9). The head section Hs 'of the tuft S' continues to be pulled by the transfer device 40, while the additional tuft S '' forms the loop R ''. Gradually, the overlapping section S * detaches from the main surface 28 or the side surface 30 'of the main roller 30 and, crossing the narrower passage, that is to say the lower passage 32 , moves towards the transfer zone 42 of the transfer device 40.

By overlapping the head section Hs '' of the additional tuft S '' on the tail section Ts 'of the tuft S', the combed and continuous ribbon W is formed, transported by the transfer device 40 .

For the sake of clarity, it should be noted that the head section Hs '' of the additional tuft S '' crosses the tail section Ts 'of the tuft S', but that it is located below that -this, that is to say that it is arranged below, as is clear for the combed strip W which passes over the transfer device. This advantageously improves the carrying capacity of the ribbon on the transfer device, since the head section Hs' 'of the additional tuft S' 'does not tend to rise from the tail section Ts' of the tuft S '.

Preferably, the combed strip W passes first between the main roller 30 and the transfer device 40, through the engagement line L, undergoing a first compaction.

Then, preferably, the combed strip W passes between the compacting rollers 70a, 70b to then exit the combing zone through the end rollers 80a, 80b.

According to a preferred embodiment, the combing machine according to the present invention comprises a plurality of combing heads, for example aligned along a transverse axis, displaced by a single circular comb shaft for the respective circular combs , a single upper detachment shaft and a single lower detachment shaft for the detachment rollers, and likewise for the auxiliary rollers.

Second embodiment (Figure 11)

According to another embodiment, which substantially follows what is described above, the transfer device 40 is engaged with the main surface 28 of the main device 26 by a curved engagement part Ai, by for example by a curved part of the lateral surface 30 ′ of the main roller 30, defined in cooperation with a transfer roller 200.

For example, the trajectory of the belt 50 of the transfer device 40 is defined by said transfer roller 200.

In this embodiment, the tuft S ', and thus the combed strip, does not detach from the main surface 28 to move, without support, towards the transfer device 40, but detaches from the main surface 28 only at the end of the curved engagement part Ai, when it is already supported by the transfer device 40.

Third embodiment (Figure 12)

According to another embodiment, which substantially follows what has been described above, the main device 26 comprises a main belt 100 movable along a closed loop path, facing the outlet orifice 24 of the auxiliary rollers 20a, 20b.

For example, the trajectory of the main belt 100 is defined by a lower main roller 102 and an upper main roller 104, on which the main belt 100 is wound.

The main belt 100 has an outer surface which, in a section in front of the outlet orifice 24, forms said main surface 28 of the main device 26, against which the tuft coming from the auxiliary rollers 20a, 20b collides.

Part of the main surface 28 forms said impact zone 29.

The main surface 28 is airtight, that is to say that there are no holes or spaces for a suction current intended to maintain the tuft carried by said surface main.

Fourth embodiment (Figure 13)

According to another embodiment, which substantially follows what is described above, the combing head 1 comprises an output roller 110, disposed downstream of the impact zone 29 between the tuft S 'and the main surface 28 of the main device 26.

The imaginary outlet plane P5 is defined by passing through the axis of rotation of the outlet roller 110 and the main roller 30. This outlet plane P5 intersects the lateral surfaces of the outlet roller 110 and the main roller 30, by defining an outlet passage 112 crossed by the tuft S 'to continue on the transfer device 40.

The outlet passage 112 is narrower than the lower passage 32 formed by the lower auxiliary roller 20b with the main roller 30, as well as by the upper passage 34 formed by the upper auxiliary roller 20a with the main roller 30.

Preferably, the transfer device 40 is engaged with the main surface 28 of the main device 26 by a curved engagement part Ai, for example by a curved part of the lateral surface 30 'of the main roller 30 , defined in cooperation with said output roller 110.

For example, the path of the belt 50 of the transfer device 40 is also defined by the output roller 110.

In this embodiment, the tuft S 'does not detach from the main surface 28 to move, unsupported, to the transfer device 40, but detaches from the main surface 28 only to the end of the curved engaging part Ai, when it is already supported by the transfer device 40.

Fifth embodiment (Figure 14)

According to another embodiment, which substantially follows what has been described above, the transfer device 40 engages the main surface 28 only along said line of engagement L and, crossed by the outlet passage 112, the tuft S ′ detaches from the main surface 28 and, unsupported, it moves towards the transfer device 40.

Sixth embodiment (Figure 15)

According to another embodiment, which substantially follows what has been described above, the combing head comprises an auxiliary device 300 which transfers the tuft S 'detached by the detachment rollers 20a', 20b 'to the main device 26.

In the embodiments described above, the auxiliary device 300 comprises said auxiliary rollers 20a, 20b.

In the embodiment of Figure 15, the auxiliary device 300 instead comprises an upper auxiliary roller 20a and a lower auxiliary group 302, coupled to the upper auxiliary roller 20a, comprising an auxiliary belt 304 which follows a trajectory in closed loop, defined for example by auxiliary deflection elements 306, 308, 310, such as cylinders, rollers, corner elements and the like.

For example, the upper auxiliary roller 20a is motorized and in pressure contact with the auxiliary belt 304, to cause the movement of the latter.

The outer surface of the auxiliary belt 304, which carries the tuft S ', forms an auxiliary surface 320 of the auxiliary device 300, having a translation speed Vd.

The outlet plane P2 is defined between the lateral surface of the upper auxiliary roller 20a and the trajectory of the auxiliary belt 304 and, consequently, the outlet orifice 24.

The secondary passage 32 is defined by the minimum distance from the auxiliary surface 320 from the main surface 28.

Other embodiments

According to another embodiment, the pair 20 of auxiliary rollers 20a, 20b is placed directly downstream of the clamp 4, in front of it, and therefore fulfills the function of the detachment rollers, as described above.

In this embodiment, the detachment of the tuft S 'is carried out directly by the auxiliary rollers 20a, 20b, which then transfer the tuft S' from the inlet orifice 22 to the outlet orifice 24.

In another embodiment, the direction of rotation of the main roller opposite the outlet orifice is directed upwards and the axis of rotation of said main roller is located above the third plane.

In this embodiment, the upper auxiliary roller 20b is closer to the main surface 28 than the lower auxiliary roller 20a, the upper passage is narrower than the lower passage and the section passes through the upper passage.

According to another embodiment, the combing machine comprises electronic adjustment means adapted to adjust the speed of the main surface 28 or the speed of rotation of the main roller 30. Advantageously, it is possible to adjust the amount of overlap between the tufts using said speed control.

According to another embodiment, the position of the main surface 28, that is to say the position of the axis of rotation 30 '' of the main roller 30, is adjustable, preferably vertically and / or horizontally. Advantageously, this possibility of adjustment makes it possible to treat shorter fibers or longer fibers, as a function of the distance defined with respect to the main detachment rollers.

According to another embodiment, the combing head comprises an auxiliary device comprising a lower auxiliary roller and an upper auxiliary group, preferably having the structural and functional characteristics described above.

According to yet another embodiment, the auxiliary device comprises an upper auxiliary group and a lower auxiliary group, preferably having the structural and functional characteristics described above.

The embodiments described above should not be considered as exclusive; on the contrary, the characteristics described for one embodiment can be combined, together or separately, with one or more of the characteristics described for the other embodiments.

Innovatively, the combing machine used according to the present invention meets the needs of the sector, in that the detachment rollers have a unidirectional movement; this eliminates the kinematic mechanisms necessary to obtain a process movement with pilgrim steps.

In addition, advantageously, the combing machine used according to the invention, precisely thanks to the simplification of the above-mentioned mechanisms, makes it possible to reach high working speeds, for example of 700 strokes / minute.

It is clear that a person skilled in the art can make modifications to the combing machine described above in order to meet ancillary needs, all within the scope of protection defined in the claims which follow.

Claims (4)

1. Method for working a combing head, comprising the steps of: - detaching a tuft (S ') from a combed strip by means of a pair of detachment rollers (20a', 20b ') in continuous rotation, said tuft (S') having a first face and a second opposite face; - transfer the tuft (S ') from the detachment rollers (20a', 20b ') to an auxiliary device (300) comprising auxiliary rollers (20a, 20b) in continuous rotation; - send the tuft (S ') by means of the auxiliary device (300) to a main device (26) having a main surface (28) movable at a main speed (Va) lower than the peripheral speed (Vd) of the auxiliary rollers ( 20a, 20b) of the auxiliary device (300); - colliding the tuft (S ') against an impact zone (29) of the main surface (28) and pulling it from said main surface (28) so that a head section (Hs' ) of the tuft (S ') is arranged on the main surface (28) and directed towards an outlet passage (32; 112), while a tail section (Ts') of the tuft (S') is arranged on the auxiliary device; - form a loop (R ') between the head section (Hs') and the tail section (Ts ') of the tuft (S'); - detaching an additional tuft (S ''), sending said additional tuft (S '') by means of said auxiliary device (300) to the main surface (28), so that a head section (Hs '') of the additional tuft (S '') crosses the tail section (Ts ') of the tuft (S'), forming a continuous combed strip (W); - remove the combed strip (W) from the outlet passage (32; 112); - transfer the combed strip (W) to a transfer device (40) so that, on the transfer device (40), the head section (Hs '') of the additional tuft (S '') is crossed under the tail section (Ts ') of the tuft (S'). 2. The working method according to claim 1, in which, while the tail section (Ts ') is disposed on the auxiliary device, the hitherto first face of the tuft (S') cooperates with the auxiliary device, and then, before the tail section (Ts ') moves away from the auxiliary device, the second face of the tuft (S') cooperates with the auxiliary device. 3. Method for working a combing head, comprising the steps of: - detaching a tuft (S ') from a combed strip by means of an auxiliary device (300) comprising auxiliary rollers (20a, 20b) in continuous rotation, said tuft (S') having a first face and a second face opposite; - send the tuft (S ') by means of the auxiliary device (300) to a main device (26) having a main surface (28) movable at a main speed (Va) lower than the peripheral speed (Vd) of the auxiliary rollers ( 20a, 20b) of the auxiliary device (300); - colliding the tuft (S ') against an impact zone (29) of the main surface (28) and pulling it from said main surface (28) so that a head section (Hs' ) of the tuft (S ') is arranged on the main surface (28) and directed towards an outlet passage (32; 112), while a tail section (Ts') of the tuft (S') is arranged on the auxiliary device; - form a loop (R ') between the head section (Hs') and the tail section (Ts ') of the tuft (S'); - detaching an additional tuft (S ''), sending said additional tuft (S '') by means of said auxiliary device (300) to the main surface (28), so that a head section (Hs '') of the additional tuft (S '') crosses the tail section (Ts ') of the tuft (S'), forming a continuous combed strip (W); - remove the combed strip (W) from the outlet passage (32; 112); - transfer the combed strip (W) to a transfer device (40) so that, on the transfer device (40), the head section (Hs '') of the additional tuft (S '') is crossed under the tail section (Ts ') of the tuft (S'). 4. The working method as claimed in claim 3, in which, while the tail section (Ts ') is disposed on the auxiliary device, the hitherto first face of the tuft (S') cooperates with the auxiliary device, and then, before the tail section (Ts ') moves away from the auxiliary device, the second face of the tuft (S') cooperates with the auxiliary device.