Technical field of the invention

The present invention relates to a feeding device and to a method for feeding a continuous elongated element, in particular for the production of tyres.

State of the art

In the context of the tyre production processes, it is common processing or manipulating continuous elongated elements (for example ribbon-like elements), typically entirely of elastomeric compound or containing elastomeric compound in combination with other elements.

By the term "feeding" and the like it is meant the transport of the elongated element through a feeding point for the purpose of any type of treatment (e.g. mixing, extrusion, cutting, spreading or winding, coupling with other elements, calendering, etc.).

By "continuous elongated element" it is meant a structurally cohesive element, having a longitudinal dimension (which defines a length) much greater than the remaining dimensions (which define a width and a thickness), and having a section perpendicular to the longitudinal dimension of any shape (e.g. rectangular, circular, oval, irregular, etc.).

For example, it is known feeding a continuous elongated element to continuous processing machinery for processing in continuous the material. The feeding of the continuous elongated element to the machinery can take place in combination or not with the feeding of other ingredients.

For the purposes of the present description and/or of the claims that follow, the expression "continuous processing machinery" indicates a machinery into which the material to be processed (e.g. the continuous elongated element and/or the ingredients of the compound) for obtaining a desired product is fed in continuous (apart from the possible stop of the machinery due to maintenance, or variation of the recipe of the desired product) and from which the product is discharged by a substantially continuous flow.

The continuous processing machinery comprise the continuous mixers for the production of compounds (e.g. masterbatch, intermediate or final compounds), such as for example two screw mixers (i.e. twin screw), typically co-rotating, ring extruders (i.e. mixers having a plurality of co-rotating screws arranged in an annular arrangement), planetary extruders (i.e. mixers having a rotating central spindle and a plurality of planetary spindles arranged around, and intermeshed with, the central spindle to rotate around the central spindle and on themselves following the rotation of the central spindle). These mixers are capable of imparting an energetic mixing to the materials introduced therewith, both in the state of individual ingredients (separated or combined), and in the state of compound, even cold, and the active elements of the mixers (e.g. screws and/or spindles) are characterized along their longitudinal development by transport portions (e.g. helical threads), to advance the material, interspersed with mixing portions (for example compressive masticating elements and shear masticating elements).

The continuous processing machinery also comprises the extruders for the production of semi-finished green products (e.g. tread band, beads, etc.) used in the production of tyres, such as single-screw extruders and twin-screw extruders (typically counter-rotating), extruders for semi-finished products (e.g. profilometer), feeding extruders for fabric gumming calenders. These extruders, while inevitably imparting a low degree of mixing, essentially perform the function of pushing the compound towards the outlet mouth. They are indeed typically not able to produce a compound starting from the individual ingredients.

The continuous elongated element can be directly fed to a feeding portion of a continuous processing machinery, wherein this feeding portion typically comprises a (at least one) feeding screw, which captures and drags the continuous elongated element to a mixing and/or transporting chamber of the processing machinery. Typically, the continuous elongated element is fed to the feeding screw of the aforementioned machinery simply by gravity, for example through a hopper.

By 'substantially perpendicular ¹ with respect to geometric elements (such as straight lines, planes, surfaces, etc.) it is meant that these elements (or elements parallel thereto and incident to each other) form an angle comprised between 90°-15° and 90°+15°, preferably comprised between 90°-10° and 90°+10°, ends included.

By 'substantially parallel' with respect to the aforementioned geometric elements it is meant that these elements (or elements parallel thereto and incident to each other) form an angle comprised between 0°- 15° and 0°+15°, preferably comprised between 0°-10° and 0°+10°, ends included.

The terms 'optical', 'bright' and the like refer to an electromagnetic radiation that does not necessarily fall strictly within the optical band (i.e. the 400-700 nm band), but more generally falls within a wider neighbourhood of the optical band, for example from the ultraviolet to the infrared (for example the wavelength of the light radiation can be comprised between about 100 nm and about 10 pm).

By "matrix camera" it is meant a camera whose sensor has the pixels arranged according to a rectangular matrix having the two dimensions of comparable length (for example the two dimensions differ by less than one order of magnitude, as in the 16x9, 4x3 or 3x2 formats). By extension, a "matrix image" is a digital image acquired by a matrix camera.

By "optical axis" of a lens it is meant the line along which a rotation symmetry of the lens exists.

By "linear laser source" it is meant a laser source capable of emitting a linear laser beam, namely a laser beam lying in a "propagation plane" and having as direction of propagation a "propagation axis", belonging to the propagation plane and passing through the laser source. An intersection of the linear laser beam with a physical surface with reflective/diffusive properties, such as the surface of the elongated element, generates a 'laser line'.

Document US4718770 discloses a screw extruder comprising a feed section with a feed roller running adjacent and counter the rotation of the screw.

Document JP2008126541 A discloses an input method of a strip shaped elastomer into an extruder having a screw and a feed roll arranged parallel to the screw and rotating in an opposite direction with respect to the rotation of the screw.

Summary of the invention

Typically, the feeding screw of a continuous processing machinery is connected to, or coincides with, at least one processing screw of the machinery. For example, in a planetary extruder the feeding screw can coincide with an initial portion of the central spindle without satellites, or in a single screw extruder the feeding screw can coincide with an initial portion of the transporting and pushing screw itself. It follows that the rotation speed of the feeding screw is typically determined by the adjustment of the rotation speed of the processing screws for process reasons (e.g. adjusting the degree of mixing or adjusting the extrusion).

The Applicant has observed that typically during the feeding of a continuous elongated element to the feeding portion of a continuous processing machinery, since the elongated element is captured and dragged by the feeding screw, the flow rate of the elongated element actually fed is dependent on the rotation speed of the feeding screw. For example, as the rotation speed of the feeding screw increases, an increase in the actual feeding flow rate typically results, since the feeding screw tends to drag a greater amount of elongated element into the machinery (and vice versa).

Therefore, the Applicant has observed that when the rotation speed of the processing screw(s) varies for process reasons, an undesired variation in the feeding flow rate can occur.

The possible presence of a feeding roller adjacent to the feeding screw, as described in US4718770 and JP2008126541 A, can increase this undesired dragging, since the feeding roller cooperates with the feeding screw of the extruder to precisely drag the elastomeric ribbon-like material into the mixing chamber of the extruder itself.

The Applicant has therefore felt the need to be able to mutually decouple the rotation of the processing screw (and therefore of the feeding screw) and the flow rate of the continuous elongated element actually fed, to improve and/or diversify the production processes of compounds and/or realization process of semi-finished products. For example, the Applicant has realized that it is advantageous to be able to adjust the rotation speed of the feeding screw while keeping unchanged the flow rate of the elongated element actually fed. In particular, given a certain feeding flow rate of the elongated element, in some phases of a continuous processing process, for example of mixing process, it could be useful to increase the rotation speed of the feeding screw in order to enhance mixing, without however increasing at the same time the fed flow rate (since in this case an increase in the degree of mixing would not be obtained, as there would be more material of the elongated element to be mixed, with a consequent balancing of the two effects).

Furthermore, the Applicant has noted that, in the aforementioned circumstances, any dosage performed on the continuous elongated element upstream of the continuous processing machinery could be compromised and/or distorted by the dragging effect of the feeding screw.

The Applicant has therefore faced the problem of feeding a continuous elongated element to a continuous processing machinery in a controlled, autonomous way and independently from the type, and/or from the parameters, and/or from the conditions of the process (e.g. time trend of the process phases, rotation speed of the components, e.g. transport and mixing screws, feeding of other ingredients, etc.) in order to diversify and/or to improve the continuous processing processes and/or to be able to guarantee effective control of the flow rate actually fed (and therefore to be also able to contribute to a possible dosage of the elongated element).

According to the Applicant, the aforesaid problem is solved by a feeding device of a continuous elongated element, in which the continuous elongated element is clamped between a pair of rollers rotated by, and only by effect of, a motor and a transmission.

According to an aspect, the invention relates to a feeding device of a continuous elongated element.

The device comprises:

- a first roller and a second roller arranged side by side and having respective axes of rotation substantially parallel to each other, wherein said first roller is movable with respect to said second roller along a displacement direction for varying a mutual distance between said axes of rotation;

- a thrust actuator of said first roller towards said second roller, acting on said first roller with an adjustable thrust force;

- a motor and a transmission mechanically connected to said first and second roller for rotating said first and second roller about said respective axes of rotation with a respective rotation speed, so as to limit or prevent a variation of said respective rotation speed of said first and second roller as a consequence of an action exerted on at least one of said first and second roller not generated by said motor.

By the expression "action not generated by the motor" it is meant an action generated by any component extraneous to the motor and/or to the feeding device, such as for example and typically an action (which generates a mechanical torque) exerted on the rollers from the continuous elongated element when pulled by the continuous processing machinery, for example by the feeding screw. According to an aspect the invention relates to a plant, preferably for the production of tyres, comprising the feeding device according to the present invention and a continuous processing machinery comprising a feeding screw having a respective axis of rotation, wherein said feeding device is placed in proximity of said feeding screw. Preferably said continuous processing machinery is one of the following: planetary extruder, twin-screw mixer, ring extruder, single-screw extruder, twin-screw extruder, feeding extruder for fabric rubberizing calenders, extruder for semi-finished products.

According to an aspect the invention relates to method for feeding a continuous elongated element.

The method comprises:

- providing a first roller and a second roller arranged side by side and having respective axes of rotation substantially parallel to each other, wherein said first roller is movable with respect to said second roller along a displacement direction for varying a mutual distance between said axes of rotation;

- arranging said continuous elongated element between said first and second roller;

- pushing said first roller towards said second roller with an adjustable thrust force for clamping said continuous elongated element between said first and second roller;

- rotating said first and second roller for advancing said continuous elongated element for feeding in continuous said continuous elongated element to a feeding point with a feeding speed,

- controlling a respective rotation speed of said first and second roller so as to limit or prevent a variation of said respective rotation speed due to an action exerted on at least one of said first and second roller by said continuous elongated element.

By the expression "controlling a rotation speed" it is meant imparting a real rotation speed of the rollers substantially equal to a desired value (e.g. given by the motor as a function of the specific implemented process), and it includes the function of limiting or preventing a variation of the rotation speed of the rollers as a consequence of an action exerted on at least one of the rollers by said continuous elongated element, i.e. not generated by the motor.

According to an aspect the invention relates to a tyre production process comprising the method for feeding a continuous elongated element according to the present invention.

According to the Applicant the first and the second roller arranged side by side and having respective axes of rotation parallel to each other, with the first roller movable with respect to the second roller along a displacement direction for varying a mutual distance between the axes of rotation, make in simple way an interface of positioning (and subsequent feeding) of the elongated element. The variability of the mutual distance between the rollers allows to create space to insert the continuous elongated element and subsequently allows to bring the first roller into contact with the elongated element. In this way it is possible to adapt to different dimensions (typically thicknesses) and/or conformations of the elongated element.

Pushing the first roller towards the second roller allows to grip the elongated element and to maintain this grip (e.g. dynamically) also as the dimensions of the elongated element vary, such as the thickness of the latter, for example following section variations and/or surface defects such as protuberances and/or material deficiencies. In this way it is possible advancing the elongated element following the rotation imparted by the motor and by the transmission to the two rollers, reducing and/or avoiding slippage of the rollers with respect to the elongated element.

Furthermore, since the thrust force is adjustable, it is possible to grip the elongated element in a variable way according to the needs and/or according to the material of which the elongated element is made (e.g. a soft material could require a lower thrust force than a harder and/or stiffer one).

The thrust exerted on the first roller towards the other and the control of the respective rotation speed (e.g. the motor and the transmission are able to limit or prevent a variation of the respective rotation speed of the rollers as a consequence of an action exerted on at least one of the rollers not generated by the motor), cooperate in synergy to prevent or limit a possible dragging of the elongated element by a component extraneous to the feeding device (e.g. a feeding screw of a continuous processing machinery).

In fact, when the feeding screw pulls the continuous elongated element with a speed greater than the feeding speed given by the rotation of the rollers, thanks to the thrust force that keeps the rollers gripped on the elongated element, it is possible to prevent slippage of the elongated element through the two rollers themselves, and moreover, thanks to the motor and to the transmission as described above, it is possible to brake or preferably prevent the dragging of the rollers by the elongated element and the consequent excessive sliding of the elongated element.

In this way it is possible to feed the elongated element only following the rotation imparted to the rollers by the motor and by the transmission and therefore in a controlled, autonomous way and independently from the type and/or from parameters and/or conditions of process.

The present invention in one or more of the above aspects may have one or more of the following preferred features.

Preferably it is provided providing the feeding device according to the present invention.

Preferably pushing said first roller towards said second roller is performed by said thrust actuator. Preferably rotating said first and second roller and controlling said respective rotation speed is performed by said motor and transmission.

Typically an advancement direction of the continuous elongated element is substantially aligned to a longitudinal dimension of said continuous elongated element.

Preferably a section of the continuous elongated element substantially perpendicular to an advancement direction of the continuous elongated element has a parallelogram contour, more preferably rectangular and/or having shorter sides and longer sides with a length ratio greater than or equal to ten (i.e. the element is ribbon-like). Preferably said first and second roller contact said continuous elongated element at said longer sides (i.e. the axes of rotation of the rollers are substantially parallel to the longer sides of the section of the elongated element).

Typically the continuous elongated element consists of a homogeneous material. Preferably the continuous elongated element comprises, or it entirely consists of, an elastomeric compound.

Preferably the tyre production process comprises, subsequently to said feeding, mixing (e.g. with other ingredients or alone) or extruding said elastomeric compound (e.g. by means of said continuous processing machinery).

Preferably said displacement direction is perpendicular to both said axes of rotation. Preferably said thrust force is directed along said displacement direction. In this way the first roller is moved and kept in thrust towards the second roller in a rational way.

Preferably said motor comprises a first and a second motor unit distinct from each other and comprising respectively a first and a second motor shaft. For example, each motor unit can be: a compressed air motor, an electric motor (DC, AC, universal, brushless), a hydraulic motor, an internal combustion engine, etc.

Preferably said transmission is interposed between, to mechanically connect, said motor and said first and second roller. In this way the driving force is distributed to the rollers.

In one embodiment each roller is directly keyed onto the motor shaft of a respective motor unit (in other words, the transmission coincides with the motor shaft and each motor unit is mechanically connected directly to a respective roller).

Preferably said transmission comprises a first transmission portion which mechanically connects said first motor unit to said first roller and a second (and distinct) transmission portion which mechanically connects said second motor unit to said second roller. In this way each roller is independently motorized. Preferably said first transmission portion and said first motor unit are integral with said first roller. In this way, the movement of the first roller along the displacement direction is facilitated as it is also possible to move with the latter also the motor unit and the first transmission portion independently from the second roller and the respective second motor unit and second transmission portion. In this way the feeding device is made in simple way.

In one alternative embodiment said motor comprises one and only one motor unit. In this case, preferably said transmission is structured to allow movement of said first roller along said displacement direction while maintaining said first and second roller mechanically connected to said only one motor unit. For example, the transmission may include a chain transmission suitably dimensioned in a dynamic way to allow such movement of the first roller while maintaining the mechanical meshing with the only one motor unit.

Preferably said transmission comprises at least one input shaft and at least one output shaft, wherein preferably said input shaft receives a rotation from said motor and said output shaft rotates said first and second roller.

Preferably said first and second transmission portion comprise respectively a first and a second input shaft and respectively a first and a second output shaft.

Preferably said first and second input shaft are mechanically, more preferably rigidly, connected respectively to said first and second motor shaft for, more preferably integrally, rotating with said first and second motor shaft.

Preferably said first and second output shaft are mechanically, more preferably rigidly, connected respectively to said first and second roller for rotating said first and second roller.

The expressions "input shaft", "output shaft" refer to a direction of distribution of the driving force (i.e. from the motor to the rollers through the transmission).

Preferably said transmission, more preferably each of said first and second transmission portion, comprises a mechanical coupling between the respective input shaft and the respective output shaft for transmitting a rotation of said respective input shaft to said respective output shaft so as to limit or prevent a rotation of said respective output shaft not transmitted by said respective input shaft. Preferably said mechanical coupling comprises, more preferably consists of, a gear coupling of the type endless screw-gear wheel, proceeding from said respective input shaft to said respective output shaft (for example, said input shaft is equipped with the endless screw and said output shaft is integral with, or connected to, the gear wheel meshed to said endless screw). In this way to a rotation of the endless screw follows a rotation of the gear wheel which in turn transfers the rotation to the roller. At the same time, when the gear wheel is subjected to a mechanical torque not coming from the endless screw, the latter mechanically prevents the rotation of the gear wheel. In this way, the prevention of the variation of the respective rotation speed of the first and second roller as a consequence of the action exerted on at least one of the rollers not generated by the motor is achieved in a constructively simple way. Alternatively, or in addition, the motor itself (e.g. the first and/or the second motor unit) is able to exert a brake action when a motor shaft is subjected to a torque 'external' to (i.e. not supplied by) the motor, to impose a rotation to the rollers independent from this external torque. In one embodiment the transmission can comprise a single input shaft for a single motor shaft of the only one motor unit and a respective output shaft for each of said first and second roller. In this case, preferably said transmission comprises a respective mechanical coupling between said single input shaft and each respective output shaft, said respective mechanical coupling comprising at least one of, more preferably all, the aforementioned features of said mechanical coupling of each of said first and second transmission portion.

Preferably said transmission, more preferably each of said first and second transmission portion, is devoid of clutch members. In this way the motor always remains engaged with the rollers, further reducing the risk of a possible variation in the rotation speed of the rollers as a consequence of an action not given by the motor.

Preferably each of said first and second transmission portion comprises, more preferably consists of, a respective gearbox. In one embodiment a reduction ratio of each gearbox is greater than or equal to 1 :50, more preferably greater than or equal to 1 :40, and/or less than or equal to 1 :20, more preferably less than or equal to 1 :30. In this way it is possible to obtain a desired dragging torque at the rollers (for example as a function of the material of which the elongated element is made of, typically as a function of a viscosity of the latter).

Preferably each of said first and second transmission portion is mechanically connected to the respective roller at a first longitudinal end of said respective roller.

Typically, said rotations of said first and second roller have opposite directions (i.e. the rollers are counter-rotating).

Preferably said rotations of said first and second roller are such that linear speeds of respective side surfaces of the first and second roller are (substantially, i.e. less than 10% of the theoretical value) equal to each other. Typically the first and second roller have radius and respective rotation speeds equal to each other. In this way, the feeding of the elongated element is facilitated, reducing the risk of possible incorrect dragging by the rollers, which could, for example, abrade the surface of the elongated element.

Preferably said feeding device comprises, for respectively said first and second roller, an angular position transducer for measuring an angular position of respectively said first and second roller (e.g. an encoder). This angular position can be measured directly on the rollers, or indirectly, i.e. on elements (e.g. said first and second motor shaft, said first and second input shaft, said first and second output shaft, etc.) having respective angular position uniquely correlated with the aforementioned angular position of the rollers.

Preferably said feeding device comprises a command and control unit connected to said motor, more preferably to both said first and second motor unit, and to each angular position transducer. Preferably said command and control unit is programmed for commanding said motor at least as a function of a measurement of each angular position transducer. In this way it is possible to substantially synchronize the rotation of the first and second roller.

Preferably said feeding device comprises, for each of said first and second roller, a respective group of bearings (e.g. ball, magnetic, etc.) arranged at the first longitudinal end and/or at a second longitudinal end of the respective roller opposite to said first longitudinal end. In this way, the rollers are supported while facilitating their rotation.

Preferably each of said first and second roller comprises a respective side surface which develops with cylindrical symmetry about the respective axis of rotation. In use, the side surface of each roller is placed in contact with the continuous elongated element.

Preferably said side surface has cylindrical development. In this way the contact area with the elongated element is maximized.

In one alternative embodiment said side surface has a toothed development, i.e. it has a plurality of radial reliefs, preferably with right angles, wherein the reliefs of the first roller are intermeshed with the reliefs of the second roller. In this way the elongated element is cut into a plurality of strips along the advancement direction, favouring the capture by the feeding screw.

Preferably said side surfaces of said first and second roller are structured for gripping said continuous elongated element. Preferably said side surfaces of the first and of the second roller have a surface treatment for increasing a friction (e.g. static) coefficient with said continuous elongated element (e.g. they are knurled or embossed). In this way the retention of the elongated element by the two rollers is increased as a consequence of the thrust force.

In one embodiment said first roller can move along said displacement direction for a length greater than or equal to 5 mm, more preferably greater than or equal to 10 mm, and/or less than or equal to 30 mm, more preferably less than or equal to 25 mm.

In one embodiment, against the movement of said first roller, a minimum distance between said side surfaces of said first and second roller is greater than or equal to 2 mm, more preferably greater than or equal to 4 mm, even more preferably greater than or equal to 5 mm. In one embodiment, against the movement of said first roller, a maximum distance between said side surfaces of said first and second roller is less than or equal to 40 mm, more preferably less than or equal to 30 mm, even more preferably less than or equal to 25 mm. In this way it is possible to feed elongated elements having various dimensions (e.g. thicknesses).

Preferably said feeding device comprises a base body, more preferably rigid, which develops respectively along a longitudinal direction, a transversal direction and a height. Typically the longitudinal direction, the transversal direction and the height are substantially perpendicular to each other. Preferably the first roller is movable with respect to the base body. In one embodiment also said second roller is movable with respect to the base body for varying said mutual distance between said axes of rotation. In this way the stroke of each roller can be maintained limited.

Preferably said base body comprises a first and a second seat which at least partially house respectively said first and second roller.

Preferably said first and second seat have a respective main development direction substantially parallel to said longitudinal direction of development of the base body.

Preferably said respective axes of rotation of the first and second roller are substantially parallel to said longitudinal direction. In this way the rollers rationally occupy their respective seats.

Preferably said displacement direction is substantially parallel to said transversal direction. In this way the first roller rationally moves with respect to the base body.

Preferably said base body comprises a through opening having an inlet mouth and an outlet mouth arranged at opposite sides of said base body along said height. Preferably said through opening is interposed between said first and second seat, the first and the second seat being communicating with, and more preferably contiguous to, said through opening. In this way, a passage is made through the base body suitably arranged to interpose the continuous elongated element between the first and the second roller.

Preferably said through opening develops substantially along said height. In this way, a substantially straight passage is created for the elongated element.

Preferably said first and second roller (at least) partially obstruct said through opening (preferably narrowing a section of a tract of said through opening). In this way the first and the second roller can interact with the elongated element when inside the through opening.

Preferably said first seat comprises a first portion distal from said through opening and counter-shaped to a circumferential portion of the side surface of said first roller. Preferably said first seat comprises a second portion, contiguous to said first portion, proximal (more preferably contiguous) to said through opening and shaped to provide a sliding guide of said first roller along said displacement direction. In this way the first roller can slide along the first seat to vary a degree of encumbrance of the through opening.

Preferably said second seat is counter-shaped to a circumferential portion of the side surface of said second roller. In this way space is saved to reduce the overall encumbrances.

Optionally, said base body can comprise a further through opening, more preferably having a respective inlet mouth and a respective outlet mouth arranged at opposite sides of the base body along said height. In this way it is possible the feeding of further elements (typically not continuous elongated elements, for example granular).

Preferably said side surfaces of said first and second roller are accessible only through said through opening (e.g. through said inlet mouth). In other words, the base body surrounds the first and second roller except at the through opening. In this way, the moving parts of the device are enclosed within the base body and its intrinsic safety is increased.

Preferably said base body comprises a set of base elements assemblage together to form said base body. Preferably said base elements have mainly planar development along the longitudinal direction and the transversal direction and they are stacked along said height. In this way it is possible to assemble the whole device in a simple way by stacking of the base elements.

Preferably said set of base elements comprises at least three base elements, more preferably three and only three base elements.

In one embodiment, a length of said inlet mouth of said through opening along said longitudinal direction is greater than or equal to 20 cm, more preferably greater than or equal to 60 cm, for example greater than or equal to 90 cm, and/or less than or equal to 150 cm, more preferably less than or equal to 120 cm, for example less than or equal to 100 cm. The aforesaid dimensions allow to easily feed elongated elements having various dimensions (typically between a little less than 20 cm and about 120 cm of transversal width).

Preferably said base body comprises a respective housing seat respectively for said transmission and for said groups of bearings.

Preferably one or more (more preferably at least two) base elements comprise respective recesses shaped for forming, with said base elements assembled to form said base body, said first and second seat and or said housing seats. In this way it is possible to realize seats, such as typically the housing seat of the groups of bearings, substantially totally internal to the base body and/or having pronounced undercuts, for example to promote the intrinsic safety of the feeding device and/or to further limit its encumbrances.

Preferably said base elements comprise male-female couplings at mutually facing surfaces shaped to centre said base elements with respect to each other along the longitudinal and transversal directions. In this way it is made easier the stacking of the base elements.

Preferably said base body, more preferably a base element comprising said outlet mouth of said through opening, comprises a thermal conditioning circuit, more preferably for cooling. In fact, the feeding device is typically arranged in the vicinity of a continuous processing machinery, which usually operates at high temperatures, potentially harmful to the feeding device. In the case of the thermally conditioned base element, it acts as thermal break for the remaining base elements.

Preferably said thrust actuator comprises a first actuator element operatively connected to a first longitudinal end of said first roller, more preferably it also comprises a second actuator element operatively connected to a second longitudinal end of the first roller opposite to the first. For example, each actuator element can be a hydraulic or pneumatic piston (preferably with double action), or a linear electric actuator. In this way the movement of the first roller is easily controlled and the thrust force can be imparted on the first roller in a uniform manner.

Preferably said thrust force is adjusted as a function of a viscosity of said continuous elongated element. In this way it is possible to adapt the device to the various elongated elements, favouring their feeding and reducing the risk of damaging the elongated element and/or of not providing sufficient thrust force to move it.

Preferably said command and control unit is connected to said thrust actuator to adjust said thrust force as a function of a value representative of a viscosity of said continuous elongated element. The value representative of the viscosity can be measured and transmitted directly to the unit or entered manually by the operator.

According to an aspect the invention relates to a feeding apparatus of a continuous elongated element comprising an advancement system for advancing said continuous elongated element along a first tract with an advancement direction, said advancement system comprising the feeding device according to the present invention placed at an outlet of the first tract for feeding in continuous with a feeding speed said continuous elongated element to a feeding point corresponding to said outlet of said first tract.

The terms 'upstream', 'downstream', 'in an intermediate, initial, terminal position', 'inlet', 'outlet' and the like refer to relative positions or placements between elements and/or regions of the apparatus with reference to the advancement direction of the continuous elongated element.

Preferably the feeding apparatus comprises a measuring system for measuring in continuous on said continuous elongated element a quantity suitable for evaluating an actual flow rate of said continuous elongated element fed in continuous to said feeding point.

By 'flow rate' of a continuous elongated element it is meant the quantity (in terms of volume or mass, linked to each other by the density of the material) of continuous elongated element which passes through a point per unit time.

Preferably the feeding apparatus comprises a respective command and control unit connected to said advancement system and to said measuring system and programmed for commanding in continuous said advancement system for adjusting in continuous said feeding speed as a function of said measured quantity and of a reference value of feeding flow rate of said continuous elongated element in said feeding point.

In this way the feeding apparatus can dose the continuous elongated element, i.e. it can feed in continuous this element to the feeding point (e.g. to a continuous processing machinery) controlling its actual flow rate.

In fact, in case of 'irregular' continuous elongated element (i.e. having a cross section that varies moving longitudinally along the elongated element), it may not be sufficient, for some applications, to control the feeding speed in order to control the actual flow rate. The aforesaid feeding apparatus, thanks to the measurement of the quantity suitable for evaluating the actual flow rate and to the control of the feeding speed as a function of such quantity, thanks to the feeding device according to the present invention, allows the dosage also of ‘irregular’ elongated elements.

By the expression " in continuous" referred to an operation relating to the continuous elongated element it is meant the temporally close repetition of this operation in order to spatially resolve this elongated element in an appropriate way, for example so that this operation is performed on successive contiguous points of the elongated element longitudinally distant from each other in the order of the centimetres or even less than one centimetre.

Preferably the command and control unit of the feeding apparatus is operatively connected to, more preferably comprises, said command and control unit of the feeding device.

Preferably said quantity comprises, more preferably it corresponds to, geometrical information sufficient for calculating, at least in an approximate way, a value representative of an areal extension of a section of said continuous elongated element on a plane substantially perpendicular to said advancement direction.

Preferably said measuring system comprises at least one optical detection device for detecting in continuous in a detection point along said first tract said geometrical information. In this way, a contactless detection is performed not to disturb the advancement of the elongated element.

In one alternative embodiment, said quantity can be a mass per unit length (i.e. the measuring system dynamically weighs a longitudinal tract of the continuous elongated element while it advances). Preferably said geometrical information comprises an altimetric profile of at least a portion of a contour of said section with respect to a reference height. In this way, it is possible to calculate the areal extension of the section taking into account the actual profile of at least a portion of the contour of the section. In this way it is possible comprising in the calculation of the areal extension possible (e.g. superficial, such as lacks and/or excesses of material, variations in the shape of the section, etc.) defects of the elongated element to improve the accuracy of the calculation of the areal extension of the section.

Preferably said optical detection device comprises a matrix camera, having an optical axis, and a linear laser source, capable of emitting a linear laser beam having a propagation axis (arranged at a certain angle with respect to the optical axis, for example 40°). In this way it is possible to acquire the geometrical information by means of laser triangulation which allows a scan by lines of a surface of the elongated element, i.e. a substantially punctual scan along the longitudinal dimension, to obtain the altimetric profile of at least a portion of the contour of the section (and therefore with the advancement of the elongated element, the altimetric profile of at least a portion of the aforementioned surface of the elongated element is obtained).

In one embodiment, said geometrical information comprises an altimetric profile of a (substantially whole) contour of said section. Preferably said measuring system comprises a further optical detection device arranged at opposite side of the continuous elongated element with respect to said optical detection device. Preferably the further optical detection device comprises the same features of the aforementioned optical detection device. In this way, the accuracy of detection of the geometrical information by means of laser triangulation is increased, since it is possible to detect possible surface defects also at a further surface of the elongated element (e.g. up to also substantially detect the whole geometric contour of the section).

Preferably said command and control unit of said feeding apparatus is programmed for calculating in continuous a value representative of an areal extension of said section as a function of said geometrical information. In this way, being the areal extension of the section substantially punctual along the advancement direction, it is possible to achieve a high dosing accuracy since it is possible to evaluate the actual flow rate in a substantially punctual way (as described below).

Preferably said command and control unit of the feeding apparatus is programmed for calculating in continuous a theoretical value of the feeding speed as a function of a ratio between said reference value of feeding flow rate and said value representative of the areal extension of the section. In this way the actual flow rate at the feeding point is implicitly evaluated and it is compared with the reference value of the flow rate.

Preferably adjusting in continuous said feeding speed comprises setting said feeding speed equal to said theoretical value. In this way the flow rate actually fed to the feeding point corresponds to the desired flow rate value.

Preferably commanding in continuous said advancement system for adjusting in continuous said feeding speed comprises commanding in continuous (solely) said feeding device, more preferably commanding in continuous said motor, more preferably each of said first and second motor unit (even more preferably in a mutually independent way), for adjusting (e.g. accelerating, slowing down) said rotation of said first and second roller.

Preferably said command and control unit of the feeding apparatus is programmed for calculating (more preferably as a function of said feeding speed) a time delay spent by said section for going from said detection point to said feeding point. Preferably said command and control unit of the feeding apparatus is programmed for commanding in continuous said advancement system for adjusting in continuous said feeding speed also as a function of said time delay, more preferably when said section has reached said feeding point. In this way, the physical extension of the feeding apparatus is taken into account in the adjustment of the feeding speed (since the areal extension of the section is calculated at the detection point which typically does not correspond to the feeding point).

Brief description of the drawings

The features and the advantages of the present invention will be further clarified by the following detailed description of some embodiments, presented by way of non-limiting example of the present invention, with reference to the attached figures, in which: figure 1 schematically shows a section (along the plane BB of figure 2) of a feeding device according to the present invention; figure 2 schematically shows a top view of the feeding device of figure 1; figure 3 schematically shows a perspective view of some components of the feeding device of figure 1 ; figure 4 schematically shows a plant according to the present invention; figure 5 schematically shows a feeding apparatus according to the present invention.

Detailed description of some embodiments of the invention

In the figures, the number 999 globally indicates a feeding device of a continuous elongated element 900.

Exemplarily, the continuous elongated element 900 consists of a ribbon-like element of homogeneous green elastomeric compound. Exemplarily (figure 2) a section 200 of the continuous elongated element, perpendicular to an advancement direction 100 of the continuous elongated element (in figure 2 having a direction entering the sheet plane), is substantially rectangular (neglecting possible surface defects, not shown), for example with longer sides about 20 cm long and smaller sides about 3 cm high. Exemplarily the feeding device 999 comprises a first roller 1 and a second roller 2 arranged side by side and having respective axes of rotation 101, 102 (identified by the symbol + in figure 1) parallel to each other, wherein the first roller 1 is movable with respect to the second roller 2 along a displacement direction 103, exemplarily perpendicular to both the axes of rotation 101, 102, for varying a mutual distance D between the axes of rotation 101, 102. Exemplarily the first 1 and the second roller 2 each comprise a respective side surface 4 which develops with cylindrical symmetry about the respective axis of rotation 101, 102. Exemplarily, in use, the side surface 4 of each roller is placed in contact with the continuous elongated element 900 at the longer sides of the elongated element (figures 2 and 3).

Exemplarily the side surfaces 4 have cylindrical development and they are structured for gripping the continuous elongated element 900. For this purpose, exemplarily, the side surfaces 4 of the first 1 and of the second roller 2 have a surface treatment (schematically represented in figures 2 and 3 by means of the hatching) for increasing a static friction coefficient with the continuous elongated element 900 (e.g. they are knurled or embossed).

Exemplarily the feeding device 999 comprises a thrust actuator 5 of the first roller 1 towards the second roller 2, acting on the first roller 1 with an adjustable thrust force directed along the displacement direction 103.

Exemplarily the first roller 1 can move along the displacement direction 103 for an overall length of about 20 mm.

Exemplarily, against the movement of the first roller 1, a minimum distance between the side surfaces 4 of the first 1 and of the second roller 2 is about 5 mm, and a maximum distance is about 25 mm. Exemplarily the thrust actuator 5 comprises an actuator element 6 which consists of a double action pneumatic piston (only schematically shown), exemplarily operatively connected to a first longitudinal end 7 of the first roller 1.

Exemplarily the feeding device 999 comprises a motor 8 and a transmission 14 mechanically connected to the first 1 and to the second roller 2 to rotate the first 1 and the second roller 2 about the respective axes of rotation 101, 102 with a respective rotation speed so as to limit or prevent a variation of the respective rotation speed of the first 1 and of the second roller 2 as a consequence of an action exerted on at least one of the rollers not generated by the motor 8.

Exemplarily the transmission 14 is interposed between, to mechanically connect, the motor 8 to the first

1 and to the second roller 2.

Exemplarily the motor 8 comprises a first 10 and a second motor unit 11 (schematically shown in figures

2 and 3) respectively comprising a first 12 and a second motor shaft 13.

Exemplarily the transmission 14 comprises a first transmission portion 15 which mechanically connects the first motor unit 10 to the first roller 1 and a second transmission portion 16 which mechanically connects the second motor unit 11 to the second roller 2. Exemplarily the first transmission portion 15 and the first motor unit 10 are integral with the first roller 1.

Exemplarily the first 15 and the second transmission portion 16 comprise respectively a first 17 and a second input shaft 18 and respectively a first 19 and a second output shaft 20.

Exemplarily (figure 3) the first 17 and the second input shaft 18 are rigidly mechanically connected respectively to the first 12 and to the second motor shaft 13 to rotate integrally with the first and the second motor shaft, and the first 19 and the second output shaft 20 are rigidly mechanically connected respectively to the first 1 and to the second roller 2 for rotating the rollers.

Exemplarily each transmission portion 15, 16 comprises a mechanical coupling (not shown) between the respective input shaft 17, 18 and the respective output shaft 19, 20 for transmitting a rotation of the respective input shaft 17, 18 to the respective output shaft 19, 20 so as to limit or prevent a rotation of the respective output shaft 19, 20 not transmitted by the respective input shaft 17, 18. Exemplarily the mechanical coupling consists of a gear coupling of the type endless screw-gear wheel proceeding from the respective input shaft 17, 18 to the respective output shaft 19, 20 (for example, not shown, the input shaft is equipped with the endless screw and the output shaft is integral with the gear wheel intermeshed with the aforementioned endless screw). In this way it is the geometry of the mechanical coupling that physically prevents a rotation of the respective output shaft of the transmission portions if not transmitted by the respective input shaft (the rotation of the gear wheel is prevented as it cannot generate a corresponding rotation of the endless screw about the respective axis, being allowed only a transmission of motion in the opposite direction, i.e. from the endless screw to the gear wheel). Exemplarily each transmission portion 15, 16 is devoid of clutch members.

Exemplarily each transmission portion 15, 16 is constituted by a respective gearbox having a reduction ratio equal to 1:40 (i.e. a torque exerted by the respective motor shaft connected to the transmission portion is multiplied by forty at the output of the gearbox, while a rotation speed of the input shaft is divided by forty at the output shaft of the gearbox. In the jargon, this motor-gearbox coupling is called gear motor).

Exemplarily (figures 2 and 3) each transmission portion 15, 16 is mechanically connected to the respective roller 1, 2 at a first longitudinal end 7, 87 of the respective roller.

Exemplarily the feeding device 999 comprises, for each roller, a respective angular position transducer 50 (e.g. an encoder) for measuring an angular position of the first 1 and of the second roller 2 respectively. Exemplarily this angular position is measured indirectly at the first 19 and the second output shaft 20, which, being rigidly connected to the respective roller, have a respective angular position uniquely correlated with the aforementioned angular position of the rollers.

Exemplarily the feeding device 999 comprises a command and control unit 60 connected to the first 10 and to the second motor unit 11 and to each angular position transducer 50.

Exemplarily the feeding device 999 comprises, for each roller, a group of ball bearings 70 arranged at the first longitudinal end 7, 87 (not shown) and at a second longitudinal end of the respective roller opposite to the first longitudinal end 7, 87

Exemplarily the feeding device 999 comprises a rigid base body 21 which develops respectively along a longitudinal direction 201 , a transversal direction 202 and a height 203 perpendicular to each other. Exemplarily the first roller 1 is movable with respect to the base body 21.

Exemplarily the base body 21 comprises a first 22 and a second seat 23 shaped to at least partially house respectively the first 1 and the second roller 2, the first 22 and the second seat 23 exemplarily having a respective main development direction substantially parallel to the longitudinal direction 201 of development of the base body 21.

Exemplarily the respective axes of rotation 101, 102 of the first 1 and of the second roller 2 are parallel to the longitudinal direction 201 and the displacement direction 103 is parallel to the transversal direction 202.

Exemplarily the base body 21 comprises a through opening 24 which develops the height 203 and having an inlet mouth 25 and an outlet mouth 26 arranged at opposite sides of the base body 21 along the height 203. Exemplarily the through opening 24 is interposed between the first 22 and the second seat 23, the first and second seats being communicating with, and contiguous to, the through opening 24.

Exemplarily a length L of the inlet mouth 25 along the longitudinal direction 201 is equal to about 30 cm. Exemplarily the first 1 and the second roller 2, when housed respectively in the first 22 and in the second seat 23, partially obstruct the through opening 24, narrowing a section of a tract of the through opening 24.

Exemplarily the first seat 22 comprises a first portion 27 distal from the through opening 24 and countershaped to a circumferential portion of the side surface 4 of the first roller 1 , and a second portion 28, contiguous to the first portion 27 and to the through opening 24 and shaped to make a sliding guide of the first roller 1.

Exemplarily the second seat 23 is counter-shaped to a circumferential portion of the side surface 4 of the second roller 2.

Exemplarily the base body 21 comprises a further through opening 29, having a respective inlet mouth 30 (shown in figure 2) and a respective outlet mouth (not shown) arranged at opposite sides of the base body 21 along the height 203.

Exemplarily the side surfaces 4 of the first 1 and of the second roller 2 are accessible only through the through opening 24 (e.g. through the inlet mouth 25).

Exemplarily the base body 21 comprises a set of three base elements 31 which can be assembled together to form the base body 21. Exemplarily the base elements 31 have a mainly planar development (e.g. plates) along the longitudinal direction 201 and the transversal direction 203 and are stacked along height 203.

Exemplarily the base body 21 comprises a respective housing seat 32, 33 for the transmission 14 and for the groups of ball bearings 70 respectively.

Exemplarily two base elements 31 (e.g. a first and a second base element 31 proceeding along the height 203 in a direction concordant with the advancement direction 100, figure 1) comprise respective recesses shaped for forming, with the base elements 31 assembled to form the base body 21, the first 22 and the second seat 23 and the housing seats 32, 33. Exemplarily the housing seat 33 of the groups of ball bearings 70 is inside the base body 21 once assembled the base elements 31, while the housing seat 32 of the transmission 14 communicates with the outside (e.g. it is open in correspondence to at least one of its upper faces).

Exemplarily the base elements 31 comprise, as shown in figure 1, male-female couplings at mutually facing surfaces shaped to centre the base elements 31 with respect to each other along the longitudinal 201 and transversal 202 directions.

Exemplarily a base element 31 comprising the outlet mouth 26 of the through opening 24 comprises a cooling circuit (not shown).

In use, the feeding device 999 allows to perform method for feeding a continuous elongated element 900.

Exemplarily the continuous elongated element 900 is arranged between the first 1 and the second roller 2 and the first roller 1 is pushed by the thrust actuator 5 towards the second roller 2 with a thrust force for gripping the continuous elongated element 900 between the first 1 and the second roller 2. Exemplarily the thrust force is adjusted as a function of a viscosity of the continuous elongated element. For this purpose, the command and control unit 60 is exemplarily connected to the thrust actuator 5 to adjust the thrust force as a function of a value representative of a viscosity of the continuous elongated element.

Exemplarily the motor 8 is activated to rotate the first 1 and the second roller 2 for advancing the continuous elongated element 900 for feeding in continuous the continuous elongated element to a feeding point A with a feeding speed.

Exemplarily a respective rotation speed of the first 1 and second roller 2 is controlled (e.g. by the motor 8 and by the transmission 14) so as to limit or prevent a variation of the respective rotation speed due to an action exerted on at least one of the rollers by the continuous elongated element 900.

Exemplarily the rotations of the first 1 and of the second roller 2 have opposite directions (i.e. the rollers are counter-rotating) and are such that the linear speeds of the side surfaces 4 of the first 1 and of the second roller 2 are equal to each other. Exemplarily the first 1 and the second roller 2 have radius and respective rotation speeds equal to each other.

Exemplarily the command and control unit 60 is programmed for commanding the first 10 and the second motor unit 11 as a function of a measure of each angular position transducer 50.

With reference to figure 4, the number 90 globally indicates a plant comprising the feeding device 999 according to the present invention and a continuous processing machinery 80 comprising a feeding screw 81 (also shown in fig. 1) having a respective axis of rotation 105, wherein the feeding device 999 is arranged in proximity of the feeding screw 81. Exemplarily the continuous processing machinery 80 is a planetary extruder, and exemplarily the feeding screw 81 coincides with an initial portion 82 of the central spindle without satellites.

With reference to figure 5, the number 99 globally indicates a feeding apparatus for a continuous elongated element 900 comprising an advancement system 91 for advancing the continuous elongated element 900 along a first tract 110 with the advancement direction 100, the advancement system 91 comprising the feeding device 999 according to the present invention arranged at an outlet of the first tract 110 for feeding in continuous with a feeding speed the continuous elongated element 900 to the feeding point A corresponding to the outlet of the first tract 110.

Exemplarily the feeding apparatus 99 includes a measuring system 92 for measuring in continuous on the continuous elongated element a quantity suitable for evaluating an actual flow rate of the continuous elongated element fed in continuous to the feeding point A.

Exemplarily the quantity suitable for evaluating an actual flow rate of the continuous elongated element corresponds to geometrical information relating to the section 200 of the continuous elongated element 900. Exemplarily the geometrical information comprises an altimetric profile of at least a portion (not shown) of a contour of the section 200 with respect to a reference height (e.g. a side surface of a support roller 403 of the advancement system 91 on which the elongated element rests advancing). Exemplarily the measuring system 92 comprises a single optical detection device 94 (shown schematically) for detecting in continuous in a detection point R along the first tract 110 the altimetric profile of the portion of the contour of the section facing the optical detection system 94, with respect to the side surface of the support roller 403. For this purpose, exemplarily, the optical detection device 94 is based on the laser triangulation technology and it comprises a matrix camera (not shown), having an optical axis 300, and a linear laser source (not shown), adapted to emit a linear laser beam 301 having a propagation axis (which exemplarily forms an angle of about 40° with the optical axis 300).

In one embodiment (not shown), the measuring system can comprise a further optical detection device comprising the same features of the optical detection device and arranged at opposite side of the elongated element with respect to the single optical detection device 94 (i.e. below the elongated element) for detecting an altimetric profile of a further portion of contour of the section at a further detection point offset, along the longitudinal development of the elongated element, with respect to the support roller 403 (so that the latter does not interfere with the detection).

Exemplarily the feeding apparatus 99 comprises a respective command and control unit 93 connected to the advancement system 91 and to the measuring system 92 and which exemplarily comprises the command and control unit 60 of the feeding device 999.

Exemplarily the command and control unit 93 of the feeding apparatus 99 is programmed for commanding in continuous the advancement system 91 for adjusting in continuous the feeding speed as a function of the quantity measured by the measuring system 92 and of a reference value of feeding flow rate of the continuous elongated element 900 in the feeding point A.

For example, the command and control unit 93 of the feeding apparatus 99 is exemplarily programmed for calculating in continuous a value representative of the areal extension of the section 200 as a function of the altimetric profile and for calculating in continuous a theoretical value of the feeding speed as a function of a ratio between the reference value of feeding flow rate and the value representative of the areal extension of the section 200. Exemplarily adjusting in continuous the feeding speed comprises setting the feeding speed equal to the theoretical value, and commanding in continuous the advancement system 91 for adjusting in continuous the feeding speed exemplarily comprises commanding in continuous each of the motor units 10, 11 for adjusting (e.g. accelerating, slowing down) the rotation of the first 1 and second rollers 2.

Exemplarily the command and control unit 93 of the feeding apparatus 99 is programmed for calculating as a function of the feeding speed a time delay spent by the section 200 for going from the detection point R to the feeding point A and for commanding in continuous the advancement system 91 for adjusting in continuous the feeding speed also as a function of the aforementioned time delay (e.g. when the section 200 has reached the feeding point A).

Exemplarily the first tract 110 comprises a detection portion 111 which contains the detection point R, wherein exemplarily an inlet of the detection portion 111 coincides with an inlet of the first tract 110. Exemplarily the first tract 110 comprises a buffering portion 112 arranged downstream of, and continuous to, the detection portion 111, wherein exemplarily an outlet of the buffering portion 112 coincides with an outlet of the first tract 110.

Exemplarily the advancement system 91 is suitable for subjecting to tension the continuous elongated element along both the detection portion 111 and along the buffering portion 112, wherein exemplarily a reference tension along the buffering portion 112 is lower than a reference tension along the detection portion 111 (as shown by the bend formed by the elongated element). The lower tension along the buffering portion 112 provides for abundance of material to avoid that, following the adjustment of the feeding speed by means of the advancement device 999, the elongated element can be excessively subjected to stretching (which could damage it and/or break it).

Exemplarily the feeding apparatus 99 comprises, respectively for the detection portion 111 and the buffering portion 112, a respective tension sensor 95, 96 suitable for detecting in continuous, exemplarily without contact, a tension of the continuous elongated element along a respective one among the detection portion 111 and the buffering portion 112.

Exemplarily the command and control unit 93 of the feeding apparatus 99 is connected to each tension sensor 95, 96.

Exemplarily the advancement system 99 comprises, for the detection portion 111 and the buffering portion 112 respectively, a respective advancement device 97, 98 arranged at an inlet of respectively the detection portion 111 and the buffering portion 112, and structured for adjusting an advancement of the continuous elongated element. Exemplarily the advancement devices 97 and 98 are structured for respectively braking and advancing the continuous elongated element.

Exemplarily each advancement device 97, 98 is structured for gripping the continuous elongated element. Exemplarily each advancement device 97, 98 comprises a main roller M controllable by the command and control unit 93 of the feeding apparatus 99 and a further roller F (optionally also controllable by the command and control unit 93 of the feeding apparatus 99) arranged parallel to, and kept in thrust against, the main roller M.

Exemplarily the command and control unit 93 of the feeding apparatus 99 is also programmed for comparing in continuous the tension detected respectively along the detection portion 111 and the buffering portion 112 with a respective reference tension and for commanding in continuous the respective advancing device 97, 98 as a function of the respective comparison between the tension detected respectively along the detection portion 111 and the buffering portion 112 and the respective reference tension.

Exemplarily the apparatus 99 comprises, upstream of the first tract 110, a centring portion for centring the elongated element. At this centring portion, the apparatus 99 exemplarily comprises a further advancement device 400 for dragging the elongated element into unloading from a possible storage device (not shown, e.g. a pallet, a reel, etc.), a further tension sensor 401 for detecting a tension of the elongated element along the centring portion and a pair of rollers with vertical axis 402 (only one is visible) for centring (e.g. by torsion) the elongated element in collaboration with the further advancement device 400 and/or with the advancement device 97 located at the inlet of the detection portion 111. Exemplarily the command and control unit 93 of the apparatus 99 is connected to the further detection device 400 and to the further tension sensor 401.