EP1090173A1

EP1090173A1 - Anti-balloon device for spinning machine or twisting frame

Info

Publication number: EP1090173A1
Application number: EP99925218A
Authority: EP
Inventors: Daniele Petraz
Original assignee: Scaglia SRL
Current assignee: Scaglia SRL
Priority date: 1998-06-26
Filing date: 1999-06-17
Publication date: 2001-04-11
Also published as: WO2000000684A1; AU4159699A; WO2000000684B1

Abstract

Anti-balloon device for a spinning machine or twisting frame, advantageously for elastic yarns, comprising at least a spindle (11), mounted rotatable on a support (17) and associated with rotation means (12), a cop (13) to wind the yarn (14) being able to be removably inserted on the spindle (11). The device comprises a container (18) consisting of two half-shells (18a, 18b) which can be coupled with each other to define a cavity (15) suitable to accommodate the cop (13) with the function of limiting the balloon. At least one half-shell (18a) is selectively movable between a closed position, in which it is parallel to the spindle (11) and coupled with the other half-shell (18b) to enclose the cop (13) inside the cavity (15), and an open position in which it is inclined with respect to the spindle (11) and detached from the other half-shell (18b) to allow the cop (13) to be removed from the spindle (11) without interference.

Description

ANTI-BALLOON DEVICE FOR SPINNING MACHINE OR TWISTING FRAME

* * * * *

FIELD OF THE INVENTION This invention concerns an anti-balloon device as set forth in the main claim.

The invention is applied in the textile field in spinning machines and twisting frames, and more particularly in twisting frames for elastic yarn and in coating and covering machines . The device according to the invention can be applied both to textile machines equipped with spindles mounted solid on a spindle-bearing block and also to textile machines equipped with spindles which can move laterally with respect to the spindle-bearing block to assume a position of non- interference with the guiding, tensioning and unwinding devices thereabove.

BACKGROUND OF THE INVENTION The general structure of a spinning machine or twisting frame, wherein a plurality of spindles arranged in rows on a spindle-bearing block is made to rotate by drive means, is well-known in the state of the art.

One known problem which affects productivity and the speeds of rotation which can be obtained with traditional spindles concerns the formation of a loop or balloon outside the spindle, as the thread is being unwound.

If a large balloon is formed, it creates differences in tension between one point and another of the thread, and causes an uneven winding which has a negative effect on the final product. Moreover, a balloon which is too large creates a limit to the height of the cops which can be used, so that the productivity of the spinning machine is also reduced.

It should be noted that the energy consumed to drive the spindles increases in a linear manner with height, which is not therefore a particularly critical factor; on the other hand, it is cubed as the diameter increases, which means that the diameter of the spindle needs to be limited so as not to increase consumption excessively.

To overcome these shortcomings, there has been a proposal to use fixed, tubular containers, arranged around the rotary spindle, which limit the expansion of the balloon to a reduced value . If on the one hand this type of container solves the problem of not having too large a balloon, on the other hand it creates a plurality of operational problems in handling the cops of yarn, particularly at the beginning and end of the winding cycle. In fact, the presence of yarn-guiding, tensioning and/or unwinding devices above the spindle makes it difficult if not impossible to remove the cop axially without inclining it with respect to the axis of the spindle.

The inclination of the cop, however, is impeded by the anti-balloon container which, even when it allows the cop to be removed, creates a serious danger of the wound yarn rubbing against its upper edge, consequently damaging the yarn which may even have to be discarded.

Another problem is the continuous rubbing of the yarn against the inner walls of the tubular container which, in the case of thin elastic yarn such as that used for women's stockings, may even lead to the yarn itself breaking.

The state of the art also includes spindles which can pivot from a position wherein the yarn is wound to a position wherein the cop is removed/inserted; such spindles are taken to a position of non-interference with the guiding and tensioning devices thereabove .

These movable spindles, however do not solve the problem of limiting the balloon and therefore they are of limited use and application, particularly in the case of thin and ultra-thin yarn such as that used for women's stockings or similar. Document DE-A-3035008 discloses a device wherein the spindle on which the yarn is wound is movable, with respect to the fixed frame, between a vertical position, wherein it is aligned with the drawing rollers of the yarn, and a position wherein the yarn is removed/inserted, which is inclined with respect to the vertical axis on which the drawing rollers lie. The container which winds the yarn is made of two half-shells, one of which is attached to the fixed frame and remains constantly in a vertical position, while the other is associated with the spindle and is movable therewith to assume the inclined posit-ion too. This device, however, has the disadvantage that it is complex and has a large number of moving parts: in fact, to disconnect the two half-shells, the spindle and the relative support are also inclined, thus removing them from their natural, vertical operating position, in alignment with the yarn drawing means, to take them to an inoperative, inclined position.

The present Applicant has devised and embodied this invention to overcome these shortcomings, which businessmen operating in this field have long complained of.

SUMMARY OF THE INVENTION The invention is set forth and characterised in the main claim, while the dependent claims describe other characteristics of the main embodiment. The purpose of the invention is to achieve an anti-balloon device for spinning machines or twisting frames, which can be used particularly, though not exclusively, for elasticised and thin yarns, such as for example yarns for women's stockings or similar, which will solve the problem of limiting the balloon and, at the same time, will eliminate the risks of damaging or breaking the yarn, particularly when the full cop is removed from the spindle. According to the invention, a tubular container is arranged around and coaxial to the spindle; its function is to limit the amplitude of the balloon which is formed while the yarn is winding onto the cop, eliminating all the problems which too large a balloon entails during the yarn- winding steps. The tubular container is made in two parts, or half-shells, mounted on the stationary structure in such a manner that they can be coupled with each other and that at least one of them is movable with respect to the other.

According to one characteristic of the invention, at least one half-shell is selectively movable between a closed position, in which it is parallel to the spindle and coupled with the other half-shell to enclose the cop inside the anti-balloon container, and an open position in which it is inclined with respect to the spindle and detached from the other half-shell to allow the cop to be removed without interference from the spindle, maintaining the latter in an operative position.

According to a secondary characteristic of the invention, the two half-shells are temporarily maintained in the closed position by clamping means, while the correct coupling of the half-shells is facilitated by the presence of mating centering means in corresponding positions on both the movable parts.

According to another characteristic of the invention, during the passage from the closed position to the open position, the opening movement of one of the two parts activates lever means, cam or similar, cooperating with the bottom of the cop and suitable to raise it axially with respect to the winding position in order to facilitate its removal .

In one embodiment of this invention, the half-shells are kinematically associated with each other by means of mechanisms suitable to allow the simultaneous opening or closing of both half-shells even when only one of them is acted upon.

Another purpose of the invention is to supply an anti- balloon container, of the type closed at the top by a cover, which eliminates the problems connected with the handling of the cover, and the difficulty of finding the covers once removed, to reduce the times of insertion/removal of the cops into/ from the respective spindles.

According to the invention, the upper cover is equipped with an axial hole through which the yarn enters, and constraining means are provided to allow the cover to selectively assume a closed position, wherein the cop is closed inside the container, and an open position, which allows the cop to be freely removed from the container, without any risks for the yarn.

According to another characteristic of the invention, the constraining means cooperate with clamping means, provided on the container, or on the cover, or on both, to ensure the cover is temporarily maintained in the closed position. BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the invention will become clear from the following description of some preferential forms of embodiment given as a non-restrictive example with the aid of the attached drawings wherein: Fig. 1 is a front view of a first embodiment of an anti- balloon device according to the invention; Fig. 2 is a side view of the anti-balloon device as shown in Fig. 1; Fig. 3 shows a first variant of the device according to the invention; Fig. 4 shows a second variant of the device according to the invention; Fig. 5 is a longitudinal section of a device according to the invention provided with an upper cover; Fig. 6 shows a detail of a first variant of the device shown in Fig . 5 ; Fig. 7 shows a detail of a second variant of the device shown in Fig. 5;

Fig. 8 shows a detail of a third variant of the device shown in Fig. 5; Fig. 9 shows a braking mechanism of the device shown in Fig. 1 in the inactive position; Fig. 10 shows the braking mechanism shown in Fig. 9 in the working position; Fig. 11 shows a variant of the braking mechanism shown in

Fig. 9 in the inactive position; Fig. 12 shows the braking mechanism shown in Fig. 11 in the working position;

Fig. 13 shows another variant of the braking mechanism shown in Fig. 9 in the inactive position; and Fig. 14 shows the braking mechanism shown in Fig. 13 in the working position. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to Figs. 1-4, an anti-balloon device 10 according to the invention is shown associated with a spindle 11 mounted rotatable on a support 17 and extending axially in a shaft 12 with which a drawing belt 50 (Figs. 1 and 9-14) is suitable to cooperate selectively; the drawing belt 50 is in turn connected with a motor organ of a known type which is not shown in the drawings.

The belt 50 is suitable to make each spindle 11 rotate at a speed which in modern spinning machines and for thin yarns of the type used for women's stockings, can reach up to 32,000 rpm.

The mechanisms to feed and guide the yarn and every other element which is conventionally included in spinning machines or twisting frames are taken as known and are not described in any detail here.

Some examples of braking mechanisms 51, 52 and 53 of the spindle 11 will be described in detail later. A cop 13 is axially engaged on the spindle 11 and is defined by a central body 13a to position the yarn 14 and by flanges 13b, upper and lower, to retain the yarn 14.

The support 17 may be of the fixed type, or movable laterally to assume a position suitable for the removal and insertion of the cop 13, not interfering with the guiding, tensioning and unwinding devices located thereabove and not shown here .

According to the invention, a tubular container 18 is associated with the support 17 and has a central cylindrical cavity 15, coaxial with the spindle 11, the function of which is to limit the balloon which forms around the cop 13 during the winding process .

The container 18 consists of two parts, or half-shells, 18a and 18b which can be temporarily coupled with each other, of which at least one is movable with respect to the other by means of a movement of rotation around a pin 24.

The half-shells 18a and 18b are suitable to be selectively taken into a first closed position, in which they enclose the cop 13 inserted onto the spindle 11, or into a second open position, shown in Figs. 1 and 4 by a line of dashes, which allows the cop 13 to be removed freely, in this case by means of a knob 21, without any risk of friction between the yarn 14 and the container 18. In a first version, shown in Figs. 1 and 2, the lower inner portion of the half-shells 18a and 18b pivots on the support 17 by means of respective pins 24 provided in proximity of the axis of rotation of the spindle 11, that is to say, in a position inside the lateral space of the container 18.

Each half-shell 18a and 18b is suitable to rotate around its own pin 24 to move from a vertical closed position to an inclined open position, in this case substantially at 45°, and vice versa.

A bevelling 26, made on the lower outer portion of each half-shell 18a and 18b (Fig. 2), allows to take the half- shells 18a and 18b to the angled open position and also to limit the angle of inclination to pre-defined values. In the embodiment shown in Fig. 3, wherein it is provided that only one of the two half-shells, in this case 18a, can be opened with respect to the other half-shell 18b, the opening movement of the half-shell 18a around the pin 24 automatically causes the axial lifting of the cop 13 with respect to the spindle 11.

This axial lifting is obtained by the action of a cam element 34, made in a single piece on the movable half-shell

18a, which acts on the lower flange 13b of the cop 13 during the step when it passes from the first closed position to the second open position.

The cam element 34, in this case, attached to the pin 24 on which the half-shell 18a rotates, functions as a lever to lift the cop 13 with respect to the winding position indicated by a line of dashes 113 in Fig. 3, and allows the cop 13 to be easily removed from above.

Since the lifting of the cop 13 is perfectly axial, there is no risk of friction between the yarn 14 and the inner wall of the fixed half-shell 18b. It is understood that the cam element 34^' may be replaced by any similar means suitable to axially raise the cop 13 during the opening movement of the movable half-shell 18a. According to a variant which is not shown here, both the half-shells 18a and 18b, movable around the respective pins 24, are equipped with the cam element 34 to lift the cop 13. In the embodiment shown in Fig. 1, toothed wheels 25, engaging with each other, are keyed onto the pins 24 of the two half-shells 18a and 18b and enable the two half-shells 18a and 18b to move simultaneously to the closed position, or to the open position, even if only one of the half-shells 18a or 18b is acted upon.

In another version of the invention, shown in Fig. 4, it is the lower outer portion of the two half-shells 18a and 18b, rather than the inner portion as in the previous embodiment, which pivots on the support 17 by means of the respective pins 27.

This embodiment allows to take the two half-shells 18a and 18B to a position of maximum opening wherein they can also position themselves horizontally, with the advantage that the cop 13 can be more easily removed from the container 18.

In this embodiment too, the two half-shells 18a and 18b are associated with each other by means of a command mechanism 29 suitable to allow the simultaneous opening or closing of the two half-shells 18a and 18b even if only one of the half-shells 18a or 18b is acted upon.

In this case, the command mechanism 29 comprises two levers 29a and 29b, each of which is radially associated, respectively upwards and downwards, with a pin 27. The levers 29a and 29b are kinematically associated with each other by means of a connection rod 28 suitable to transmit, in the opposite direction, the movements to which one of the levers 29a or 29b is subjected, to the other lever 29b or 29a .

In both the first and the second embodiment, the two half- shells 18a and 18b are maintained in their closed position by clamping elements 30, in this case magnets, provided in corresponding positions on the coupling edges of both half- shells 18a and 18b.

In the embodiment shown, moreover, there are also mating centering elements 31 suitable to ensure a correct coupling and a correct vertical positioning of the half-shells 18a and 18b.

In this case, the centering elements 31 comprise protrusions 32, provided on the coupling edge of the half- shell 18a, suitable to be inserted in corresponding grooves 33 provided on the coupling edge of the half-shell 18b. According to a variant which is not shown here, the inner wall of the two half-shells 18a and 18b may include corrugations, protrusions, threading or similar having the function of reducing friction, by limiting the contact surface of the yarn 14 with the said inner wall. According to another variant which is not shown here, the spindle 11 may be covered by a sheath or sleeve which has the function of preventing an excessive angling of the cop 13 during the removal step in such a way as to impose a substantially coaxial removal of the cop 13 from the spindle 11.

The diameter and height of the half-shells 18a and 18b are variable according to the corresponding diameters and heights of the cops 13 and the yarns 14 wound thereon, although it is possible for half-shells 18a and 18b of different diameter and height to be associated with the same command mechanism 29.

According to another variant, the anti-balloon container 18 is closed at the upper part by a cover 20 (Figs. 5-8) shaped like a spherical cap and equipped at the center with a central through hole 16 through which the yarn 14 is made to pass .

In the embodiments shown, a mating metal bushing 19 is inserted into the through hole; the bushing 19 has smooth surfaces and bevelled edges which facilitate the passage of the yarn 14 and preserve it from damage or breakage.

According to another characteristic of the invention, the cover 20 is constrained to the container 18 by constraining means 38 suitable to allow the cover 20 to selectively assume a closed position, in which it closes the cop 13 inside the container 18, and an open position which allows the cop 13 to be freely removed from the container 18 without any risk to the yarn 14. In the embodiment shown in Fig. 5, the cover 20 consists of two movable parts, or half-caps, 20a and 20b, which can be temporarily coupled with each other, and the constraining means 38 comprise two horizontal pins 22 around which the half-caps 20a and 20b can rotate to be selectively taken to a closed position, indicated with a continuous line, or to an open position, indicated by a line of dashes.

In this embodiment, the bushing 19 is defined by two half- bushings 19a and 19b each of which is associated with the respective half-cap 20a and 20b. In the variant shown in Fig. 6, the two half-caps 20a and 20b are associated with each other by means of a command mechanism 41 suitable to allow the simultaneous opening or closing of the two half-caps 20a and 20b even if only one of them is acted upon. In this case, the command mechanism 41 comprises two levers 42a and 42b, each associated radially, respectively upwards and downwards, with a horizontal pin 23.

The levers 42a and 42b are kinematically associated with each other by means of a connection rod 44 suitable to transmit, in the opposite direction, the movements to which a first lever 42a or 42b is subjected, to the other lever 42b or 42a. Both in the first and in the second embodiment, the two half-caps 20a and 20b are maintained in the closed position by clamping elements 45, in this case magnets 46, provided in corresponding positions on the coupling edges of the half-caps 20a and 20b. In the embodiment shown in Fig. 6, moreover, there are also mating centering elements 36 suitable to ensure a correct coupling and a correct vertical positioning of the half-caps 20a and 20b.

In the embodiment shown in Fig. 7, the cover 20 is made in a single piece and in this case too the constraining means 38 consist of a horizontal pin 22.

In this embodiment, the clamping elements 45 consist of a hook 47, solid with the container 18, suitable to hook onto a retaining tooth 48 provided in a corresponding position on the perimeter of the cover 20.

In the embodiment shown in Fig. 8 too, the cover 20 is made in a single piece but in this case the constraining means 38 consist of a vertical pin 37, solid with the container 18, on which a hollow cylinder 39 is mounted, solid with the cover 20.

The hollow cylinder 39 can rotate or move vertically with respect to the pin 37, which remains stationary.

To remove the cop .13 from the container 18, first the cover 20 is lifted upwards until it reaches a position of non-interference (shown by a continuous line in Fig. 8) with the knob 21, after which the cover 20 is rotated towards the outside of the container 18 until it reaches a position of non-interference (shown by a line of dashes in Fig. 8) with the cop 13.

In this embodiment too, the clamping elements 45 consist of two magnets 46 associated, in corresponding positions, respectively on the upper edge of the container 18 and on the perimeter of the cover 20.

According to a variant, the clamping elements 45 are of the lock-in type and are provided on the pin 37 and on the hollow cylinder 39.

A first braking mechanism 51 (Figs. 1, 9 and 10) comprises a substantially U-shaped slider 55 arranged transverse to the rotation shaft 12. On the slider 55 there is a pad 56, made of a material with a high friction coefficient and suitable to cooperate with the shaft 12 to brake the rotation quickly, and two rollers 57 suitable to collaborate with the belt 50 to distance it from the shaft 12. In order to allow the slider 55 to operate, there is an aperture 17a on the support 17.

An actuator 58 of a known type is suitable to selectively displace the slider 55 between an inactive position, shown in Figs. 1 and 9, in which the pad 56 and the rollers 57 are near the shaft 12 and respectively the belt 50, but without touching them, and a working position, shown in Fig. 10, in which the pad 56 is in contact with the shaft 12 and the rollers 57 hold the belt 50 distant from the shaft 12. According to a variant, a second braking mechanism 52

(Figs. 11 and 12) comprises a gripper 60 arranged transverse to the rotation shaft 12 and having two pads 61, made of a material with a high friction coefficient and suitable to cooperate from opposite sides with the shaft 12 to brake the rotation quickly, and two rollers 62 suitable to collaborate with the belt 50 to distance it from the shaft 12.

An actuator 63 of a known type is suitable to selectively command the gripper 60 between an open position, shown in Fig. 11, in which the pads 61 and the rollers 62 are near the shaft 12 and respectively the belt 50, but without touching them, and a closed position, shown in Fig. 12, in which the pads 61 are in contact with the shaft 12 and the rollers 62 hold the belt 50 distant from the shaft 12.

According to another variant, a third braking mechanism 53 (Figs. 13 and 14) is similar to the mechanism 52 but of more restricted lateral dimensions, having the rollers 62 mounted aligned with the pads 61. The third braking mechanism 53 also comprises a second actuator 65 suitable to displace the gripper 60 transversely between a retracted position shown in Fig. 13 and an advanced position towards the shaft 12, shown in Fig. 14. Guide means 67 are provided to guide the pin 66 of the gripper 60 during the transverse displacement of the latter. Obviously, modifications and additions may be made to this invention, but they shall remain within the field and scope thereof .

For example, the clamping elements 30 of the container 18 may be of the lock-in type or consist of rings suitable to be inserted on the half-shells 18a and 18b when coupled. Alternatively, the toothed wheels 25, the rod 28 and the levers 29a and 29b may be replaced or integrated by other kinematisms such as belts, transmission shafts, racks or otherwise. Furthermore, the toothed wheels 25, the rod 28, the levers 29a and 29b and any other kinematisms possibly included can cooperate with manual activation means or with servo commanded actuators .

Moreover, the command mechanism 41 of the cover 20 can cooperate with manual activation means or with servo commanded actuators .

Moreover, the cover 20 can have any form whatsoever other than that shown here, such as, for example, cylindrical, conical, truncated cone, or otherwise.

The cover 20, moreover, may be made in more than two parts, movable and able to be temporarily coupled with each other, and the metal bushing 19 can be replaced by any other yarn-guiding means, for example, a loop.

Claims

1 - Anti-balloon device for a spinning machine or twisting frame, advantageously for elastic yarns, comprising at least a spindle (11), mounted rotatable on a support (17) and associated with rotation means (12), a cop (13) to wind the yarn (14) being able to be removably inserted on the spindle

(11), the device comprising a container (18) consisting of two half-shells (18a, 18b) which can be coupled to define a cavity (15) suitable to accommodate the cop (13) with the function of limiting the balloon, the device being characterised in that at least a first of the two half- shells (18a) is selectively movable between a closed position, in which it is parallel to the spindle (11) and coupled with the other half-shell (18b) to enclose the cop (13) inside the cavity (15), and an open position in which it is inclined with respect to the spindle (11) and detached from the other half-shell (18b) to allow the cop (13) to be removed from the spindle (11) without interference.

2 - Device as in Claim 1, characterised in that the first half-shell (18a) pivots on a corresponding pin (24, 27) mounted on the support (17) to move autonomously and independently with respect to the spindle (11) and the cop (13) .

3 - Device as in Claim 1, characterised in that the first half-shell (18a) includes lifting means (34) suitable to automatically lift the cop (13) axially during its passage from the closed position to the open position, to facilitate the removal of the cop (13) from the spindle (11).

4 - Device as in Claim 3, characterised in that the lifting means comprise cam means (34) made as an integral part in the lower portion of the first half-shell (18a) and suitable to cooperate with a lower flange (13b) of the cop (13) .

5 - Device as in Claim 2, characterised in that the pin (24) cooperates with a lower inner portion of the first half- shell (18a), the lower outer portion of the first half-shell (18a) including an inclined bevelling (26) suitable to prevent interference with the support (17). 6 - Device as in Claim 1, characterised in that the other half-shell (18b) is also movable between a closed position, in which it is substantially parallel to the spindle (11) and coupled with the first half-shell (18a) to enclose the cop (13) inside the cavity (15), and an open position in which it too is inclined with respect to the spindle (11) to allow the cop (13) to be removed.

7 - Device as in Claim 6, characterised in that clamping means (30) are provided to maintain the half-shells (18a, 18b) temporarily in the closed position. 8 - Device as in Claim 7, characterised in that the clamping means (30) are of the magnetic type.

9 - Device as in Claim 6, characterised in that centering means (31) are provided to ensure a correct coupling of the half-shells (18a, 18b) and a correct coaxial position of the half-shells (18a, 18b) with the cop (13).

10 - Device as in Claim 6, characterised in that the other half-shell (18b) also pivots on a corresponding pin (24, 27) mounted on the support (17) and in that the half-shells

(18a, 18b) are kinematically associated with each other by means of a command mechanism associated with the pins (24, 27), the command mechanism being suitable to allow the simultaneous opening or closing of the half-shells (18a, 18b) , even when only one of the two half-shells (18a, 18b) is acted upon. 11 - Device as in Claim 10, characterised in that the diameter and height of the half-shells (18a, 18b) are variable according to the corresponding diameters and heights of the cops (13) and the yarns (14) wound thereon and that half-shells (18a, 18b) of different diameter and height can be associated to the same command mechanism.

12 - Device as in any claim hereinbefore, characterised in that the support (17), together with the container (18) and the spindle (11), is movable laterally.

13 - Device as in any claim hereinbefore, characterised in that the container (18) is closed at the upper part by a cover (20) which is coupled with the container (18) by means of constraining means (38) suitable to allow the cover (20) to selectively assume a closed position, in which it closes the cop (13) inside the container (18), and an open position, which allows the cop (13) to be removed from the container (18) without interference.

14 - Device as in Claim 13, characterised in that the cover (20) comprises at least two parts (20a, 20b) which can be selectively coupled with each other, and in that the constraining means (38) comprise horizontal pin means (22, 23) suitable to connect each single part (20a, 20b) of the cover (20) to the container (18) and around which the parts (20a, 20b) are suitable to rotate.

15 - Device as in Claim 14, characterised in that centering means (36) are provided to ensure a correct coupling between the two parts (20a, 20b) .

16 - Device as in Claim 14, characterised in that the two parts (20a, 20b) are kinematically associated with each other by means of a command mechanism (41) associated with the horizontal pin means (23), the command mechanism (41) being suitable to allow the simultaneous opening or closing of the two parts (20a, 20b) even if only one of the two parts (20a or 20b) is acted upon.

17 - Device as in Claim 16, characterised in that the command mechanism (41) comprises two levers (42a, 42b) each of which is radially associated, respectively upwards and downwards, with a respective horizontal pin mean (23), the levers (42a, 42b) being kinematically associated with each other by means of a connection rod (44) suitable to transmit, in the opposite direction, the movements to which a first lever (42a or 42b) is subjected to the other lever (42b or 42a) .

18 - Device as in Claim 13, characterised in that the cover (20) is made in a single piece and that the constraining means (38) comprise horizontal pin means (22) suitable to connect the cover (20) to the container (18), the cover (20) being suitable to rotate around the horizontal pin means (22) .

19 - Device as in Claim 13, characterised in that the cover (20) is made in a single piece and the constraining means (38) comprise vertical pin means (37) suitable to connect the cover (20) to the container (18), the cover (20) being suitable both to rotate and also to move vertically with respect to the vertical pin means (37) .

20 - Device as in Claim 13, characterised in that clamping means (45) are provided to maintain the cover (20) temporarily in the closed position.

21 - Device as in Claim 20, characterised in that the clamping means (45) comprise magnets (46) .

22 - Device as in Claim 20, characterised in that the clamping means (45) are of the hook type (47) .

23 - Device as in Claim 20, characterised in that the clamping means (45) are of the snug fit type.

24 - Device as in any claim hereinbefore, wherein the rotation means comprise a shaft (12) coaxial to the spindle (11) and a drawing belt (50) able to be selectively coupled with the shaft (12), the device being characterised in that a braking mechanism (51, 52, 53) is associated with the shaft (12) and with the drawing belt (50) to stop the rotation of the spindle (11) and at the same time to detach the drawing belt (50) from the shaft (12) .

25 - Device as in Claim 24, characterised in that the braking mechanism (51) comprises a substantially U-shaped slider (55) arranged transverse to the shaft (12), and that on the slider (55) are mounted at least a pad (56) made of material with a high friction coefficient and suitable to cooperate with the shaft (12) and spacer means (57) suitable to collaborate with the drawing belt (50) to distance it from the shaft (12) .

26 - Device as in Claim 25, characterised in that an actuator (58) is provided to selectively displace the slider (55) between an inactive position in which the pad (56) and the spacer means (57) are near the shaft (12) and respectively near the drawing belt (50) but without touching them, and a working position in which the pad (56) is in contact with the shaft (12) and the spacer means (57) hold the drawing belt (50) distant from the shaft (12) .

27 - Device as in Claim 24, characterised in that the braking mechanism (52) comprises a gripper (60) arranged transverse to the shaft (12) and having a pair of pads (61) made of a material with a high friction coefficient and suitable to cooperate from opposite sides with the shaft (12) and spacer means (62) suitable to collaborate with the drawing belt (50) to distance it from the shaft (12).

28 - Device as in Claim 27, characterised in that an actuator (63) is provided to selectively command the gripper (60) between an open position in which the pads (61) and the spacer means (62) are near the shaft (12) and respectively near the drawing belt (50) but without touching them, and a closed position in which the pads (61) are in contact with the shaft (12) and the spacer means (62) hold the drawing belt (50) distant from the shaft (12) . 29 - Device as in Claim 28, characterised in that the spacer means comprise a pair of rollers (62) mounted in alignment with the pads (61) and in that a second actuator (65) is provided to displace the gripper (60) transversely between a retracted position and an advanced position towards the shaft (12).