EP0994057B1

EP0994057B1 - Supply unit of bobbins of wrapping material in a cigarette packing machine and process for pick-up and transfer of the same bobbins

Info

Publication number: EP0994057B1
Application number: EP99120328A
Authority: EP
Inventors: Valter Spada
Original assignee: SASIB SpA
Current assignee: SASIB SpA
Priority date: 1998-10-14
Filing date: 1999-10-12
Publication date: 2003-06-18
Anticipated expiration: 2019-10-12
Also published as: EP0994057A1; ITSV980058A0; ITSV980058A1; IT1305419B1; DE69908882T2; DE69908882D1

Description

The invention relates to a supply unit of bobbins of material, in particular of bobbins of wrapping material in shape of a band and in cigarette packing machines, comprising:

a) a bobbin carrier storage in which at least one bobbin is loaded;

b) a bobbin holder device in a machine using the bobbins;

c) a pick-up device provided with a clamping device and able to transport a bobbin from the bobbin carrier storage to the bobbin holder device;

d) the pick-up device being arrangeable in a preset pick-up station, in which a bobbin of the bobbin carrier storage is centered relative to the pick-up device and is withdrawn from the carrier storage by the clamping device;

e) first means for moving the bobbin carrier storage relative to the pick-up device arranged in the pick-up station, according to a first transversal direction of the axis of the bobbin to bring the bobbin in its centered position to the clamping device of the pick-up device;

f) second means for moving the pick-up device relative to the bobbin according to a path perpendicular to the first direction of movement of the bobbin carrier storage and parallel to the axis of the bobbin itself;

g) centering means comprising sensors and a control box for adjusting the centering of the bobbin relative to the clamping device of the pick-up device in the pick-up station, the said centering means control the activation and stop of the first means for moving the bobbin carrier storage;

h) the clamping device of the pick-up device comprises at least two, preferably more radial jaws able to overlap at least two diametrically opposite points or sections or more points or sections angularly distributed along the external perimeter of the bobbin on the peripheral side of the same, the said jaws being radially movable relative to a common axis parallel to the axis of the bobbin itself from a radially inward receding clamping position to a non clamping position moved radially outward;

according to the pre-characterizing part of claim 1.

A similar supply unit is also known from the document EP-A-0 710 614 according to the pre-characterizing part of claim 1.

The object of the invention is to provide a supply unit of the type described at the beginning, in which by a simple and inexpensive means it becomes possible to obtain a precise and fast centering of the bobbin relative to the clamping device of the pick-up device in the pick-up station.

The invention achieves this object with a supply unit according of the type described at the beginning and characterized in that:

i) the sensors of the centering means are fitted on each jaw and detect the corresponding points or section of the peripheral side of the bobbin or of the external peripheral edge and/or of the internal peripheral edge of the bobbin.

Some further improvements of the supply unit according to the invention are the subject of the dependent claims 2 to 9.

The invention relates also to a preferred method for the supply of bobbins using the supply unit according to any of the claims 1 to 9. The method according to the invention is characterized in that it comprises the following steps:

the axial movement of approach of the pick-up device relative to the bobbin in the pick-up station for bringing the clamping jaws of the pick-up device in a clamping position of the bobbin is stopped in a intermediate position for detection and carrying out the centering of the bobbin relative to the clamping jaws;
the clamping jaws are closed in this intermediate position and the signals emitted by the sensors pilot the control box to drive the first means for moving the bobbin carrier storage to bring the bobbin in a perfect centered position relative to the clamping jaws of the pick-up device;
the clamping jaws are opened and the pick-up device is brought in a clamping position, in which the jaws are closed again to clamp the bobbin.

Some further improvement of the method according to the invention are characterized in the dependent claims 11 to 14.

The features of the invention and the advantages derived therefrom are better evidenced by the following description of an executive example illustrated as non limiting in the attached drawings, in which:

The Fig. 1 is a schematic plan view of a making machine with a unit according to the invention.

The Fig. 2 is a partial view from the rear side of a making machine according to Fig. 1 with the unit according to the invention.

The Fig. 3 is a view in direction of transfer of the pick-up device according to the invention.

The Fig. 4 is a view in direction of the axis of the clamping jaw of the pick-up device.

The Fig. 5 is an enlarged, partial, axial cross-section of the clamping jaw according to the Fig. 4.

In the Figures from 1 to 3 the unit according to the invention is illustrated in combination with a making machine 1 that uses bands of material wound in bobbins 2, as for example a cigarette making or cigarette packing or a cellophane wrapping machine, or similar. Of the making machine 1 only the part of the body relevant to invention is illustrated. In working position of unwinding, the bobbins 2 are arranged on the front side of the making machine 1, with their axes oriented substantially perpendicular to said side. In the bottom section of at least one front side of the making machine 1, are provided at least one through tunnel, preferably two tunnels 4 side by side and parallel that are oriented parallel to the axis of the bobbins 2 in working unwinding position of the band. The through tunnels 4 have a port larger than the diameter of the bobbins 2 and are open in correspondence to the front side 101 and of the rear side 201 of the making machine itself. In each through tunnel 4 are provided transfer means 5, for one bobbin respectively. The transfer means are provided with a slide 105 that is mounted movable on guides 6 oriented parallel to the through tunnel 4 and are movable from the front side of the machine, in a position of end of stroke in which the bobbin 2 is in working unwinding position, at the rear side of the same (Fig. 1), or beyond the said rear side 201, in a position, in which they protrude beyond the rear mouth of the through tunnels 4 in a dimension larger than the diameter of the full bobbins 2 themselves, and vice versa. The movement of the slide 105 is driven by a motor thanks to a feeding screw/nut. The transfer means 5 have each directly an unwinding mandrel 7 for the bobbins 2. The mandrels 7 are of the expanding jaws 107 type, substantially known, and clamp the core 102 of the bobbins 2 from the inside. Both the drive motor of the mandrel 7 as well as of the drive actuators of the jaws 107 are themselves carried on the transfer means 5, whereas the activation of the same is controlled by the making machine, in a manner synchronized with the working units of the same, through the flexible lines and/or conduits of controls of the type commonly known. The mandrels 7 are mounted on the slides 105 of the means of transfer 5 in a manner oscillating alternatively in a position with the axis of the same oriented parallel to the direction of transfer, and that is coaxial to the axis of the bobbins 2 in the working position of unwinding, and in a position, in which the axis of the same is oriental vertically upwards. This motion is obtained by connecting the box 207 of the mandrels to the output shaft of the reducer 8 that has a preset angulation. The specific construction is described in detail in a preceding patent, issued, of the same titular with application number GE94A000105.

Along the rear side 201 of the making machine 1 a guide 9 is provided for sliding horizontally and perpendicularly to the vertical axis and to the axis of the through tunnel 4 that is for a pick-up device 10 of the full bobbins 2 from a bobbin carrier 11 storage on which are placed two stacks of full bobbins to the transfer means 5 in the end of stroke position on the rear side of the making machine 1. The bobbin carrier storage 11 houses at least one vertical stack of full bobbins that are oriented coaxial to each other and the vertical axis of which is contained in the same vertical plane, in particular parallel to the horizontal slide guide 9, from the axis of the mandrels 7 in the rear end of stroke position of the transfer means 5. Advantageously said vertical plane is provided behind the horizontal slide guide 9, whereas on the guide 9 is carried by means of a saddle 12 a further vertical guide 13, in which is mounted vertically movable a support riser 14. At its bottom end, the support riser 14 has cantilevered from its rear side a pick-up head 15 of the full bobbins 2, the central axis of which V is itself also contained in the vertical plane containing the axes of the stack of full bobbins 2 on the bobbin carrier storage 11, in the pick-up position, and the axes of the mandrels 7 oriented vertically upwards, in the position of the rear end of stroke. Therefore, the clamping head, or the vertical axis of the same parallel to the axis of the bobbins on the storage 11 can slide along an axes horizontal or parallel to the guide 9, and can be shifted between a position of pick-up of the full bobbins 2 from the stack in the storage 11, in which the axis V of the pick-up head 15 is coaxial, in a position of unloading of the bobbin picked-up on the corresponding mandrel 7 in the rear end of stroke position, in which it is coaxial to the same with a simple horizontal, rectilinear transfer.

The horizontal transfer saddle 12 has a drive motor 112 from which by means of a transmission 212 the driving motion of a transmission in shape of a threaded bolt and

female thread

312, 412 is taken. The vertical movement of the pick-up head 15 is also driven by a motor 114 carried at the top end of the sliding riser 14 and that drives the rotation by means of a belt transmission 214 of a nut 314 that is supported in a revolving manner in the riser 14 made in tubular form and that is oriented parallel to said riser 14. The nut 314 engages in a threaded bushing 414 that is integral with the guide 13 and does not rotate.

Advantageously, when the bobbins 2 are equipped with cores 102, before the full bobbin 2 can be unloaded onto one of the mandrels 7 it becomes necessary to eject the empty core 102. Therefore a gripping clamp for the cores 102 is provided in the executive form illustrated and advantageously integrated in the pick-up head 15 for the full bobbins.

With reference to the Figs. 4 and 5, the pick-up head 15, has a plurality of jaws 115 for clamping the full bobbins 2 from their external peripheral side, in order to avoid an interference with the mandrels 7 on the transfer means 5 that grip the core 102 of the bobbins 2 from the inside of the same. In the executive form illustrated, are provided three bobbin-clamping jaws 115 appropriately curved correspondingly to the external peripheral side of the full bobbins 2 and that are radially movable in a direction away from and of approach to the axes of the pick-up head 15. The bobbin-clamping jaws115 are carried cantilevered downwards at the extremity of the radial jaw-carrying arms 215 that are fixed at their radially internal extremity to radial sliders 116 of an activating unit 16. The activating unit 16 is of a type known in itself and substantially identical to the radial activating means of the jaws 107 of the mandrels 7, as for example of the type marketed by the company Rhom with the trade name TYP 538. The sliders 116 have inclined surfaces 216 that co-operate with a conjugate conical axial pusher 316, the motion of which is driven in one direction by an hydraulic or pneumatic plunger 416 and by a contrasting spring 516 in the other direction.

To the activating unit 16, or to the stationary part of the body of the same are fitted, in an intermediate position between the jaw-carrying arms 215, the arms 315 that carry cantilevered towards the bottom side and under the jaw-carrying arms 215, a coaxial end of stroke sensor ring 17. The sensor ring 17 is supported in an axial manner, elastically yielding, by means of guide bolts 117 with widened heads that are engaged in a sliding manner in coinciding holes 415 of the sensor-carrying arms 315 springs 217 being interposed between the facing sides of the sensor ring 17 and the stationary sensor carrying arms 315. The diameter of the sensor ring 17 is correspondent to an intermediate diameter of a full bobbin 2. On the side turned towards the sensor-carrying arms 315, the sensor ring 17 co-operates with sensors, for example proximity sensors, or similar 18 that are carried by the small sensor-carrying arms 315 themselves and that control the activation and the deactivation of the motor 114. The small jaw-carrying arms have in their intermediate section, determined in a manner corresponding to the radial stroke of the same and to the diameter of the cores 102 of the bobbins 2, gripping jaws 515 for the cores 102 themselves. The small jaw-carrying arms 215 are made inclined downwards in direction of their radially external extremity, whereby the core-gripping jaws 515 are provided at a level above the bobbin-clamping jaws 115 and above the full bobbin presence sensor ring 17.

The small sensor-carrying arms 315 support an additional sensor ring 19 to detect the presence of the core 102. The sensor ring 19 extends itself radially inside the core-gripping jaws 515 and has an internal and external diameter substantially corresponding to the same. The cores 102 presence sensor 19 is fitted on the small sensor-carrying arms 315 by means of external radial extensions 119. The cores presence sensor 19 is provided at the level of the top end section of the core-gripping sensor 515 and is supported in a manner analogous to the full bobbins 2 presence sensor ring 17. This arrangement is due to the particular geometric and dimensional features of the bobbins 2 and of the cores 102 and in clamping condition of the full bobbins 2, the cores 102 presence sensor ring 19 results interfering with the cores-gripping jaws 515, as it is not pushed axially upwards by the core 102, as is the case in the gripping phase of a core 102. Therefore, the cores-gripping jaws 515 a supported on springs radially yielding outward by a dimension corresponding to the gripping stroke of the bobbin-clamping jaws 115. The cores 102 gripping jaws 515 are fitted on a pair of radial guide bolts 615 with an enlarged head that are guided in radial slide holes of a small guide block 715 fixed on the small jaws-carrying arms 215 on the radially external side of the jaws themselves and as springs 815 are interposed between the small guide block 715 and the respective cores-gripping jaw 515, preferably two elicoidal springs slipped on the bolts 615. Furthermore, the cores-gripping jaws 515 are arranged inside a recess 317 made on the radially internal side of the full bobbin 2 presence sensor ring 17.

Thanks to this construction, it is possible to control both the bobbin-clamping jaws 155 as well as the cores-gripping jaws that are carried on the small arms 215 themselves with one single activator unit. The characteristic operation of the

sensors

17, 19 itself is also described in greater detail in the preceding Italian patent application, published GE94A000105.

With reference to the Figures, each jaw 115 of the pick-up head 15 has a sensor 50 to detect the corresponding section of the external peripheral edge of the bobbin in the position ready for being picked-up from the bobbins-carrying storage 11. The sensors 50 can be of any type and are formed preferably by photocells with a preset field of reading in the axial direction of the bobbin 2 that is superior to a preset axial distance from the face of said bobbin 2 in position of pick-up turned towards the pick-up head 15 from jaws 115 and inferior to the corresponding distance from the opposite face, with reference to a associated preset reading position of the pick-up head 15 itself. The reading position of the pick-up head can be any position comprised between the one of maximum distance away from the bobbin 11 in the pick-up position and the one of readiness for pick-up, that is of maximum nearness.

Apart from the clamping jaws of the bobbins, the sensors 50 can be provided also on the gripping jaws of the cores gripping clamp.

A control box 51 controls the motors or the actuators of the storage 11 of the horizontal saddle 12 and of the vertical one 14 of the pick-up head with the jaws to clamp the bobbins 2 and the jaws to grip the cores 102. Furthermore the control box drive actuators of the said jaws and in the case the sensors 50 should be provided for on the jaws of the cores-gripping clamp also the motors and the actuators of the conveyors 5.

As input, the box receives the signal of the sensors 50. The processing of the signals of the sensors 50 takes place in such a manner, whereby the motors and the motion actuators, that is of horizontal and vertical transfer of the pick-up head 15 and of movement of the bobbin 2 or of the stack of bobbins 2 in the horizontal plane of the storage 11, as well as the transfer and motion of the conveyors 5, are activated, in order to obtain a signal of presence from all the sensors 50 that read the bobbin 2 or the core 102. In this condition the bobbin 2 and/or the core 102 and the pick-up head 15 result to be axially perfectly aligned , within the range of the accepted tolerances. The direction is obviously indicated by the sensor or sensors 50 that do not read the presence of the associated part of the bobbin or of the core.

The criteria of movement can be of any type and can be managed in a manner as to optimize the handling.

Thanks to the fact that the vertical plane defined by the path of the vertical axis V of the pick-up head 15 and indicated in Fig. 1 by the axis 0 intersects with the path R in the horizontal plane of the bobbin 2 or the core on the plane of the storage 11 or on the conveyor 5 it is possible to compensate for any wrong position of the bobbin 2 and/or cores 102 when they are in the pick-up station.

Advantageously the path R of supply A of the bobbin 2 or of the stack of bobbins 2 is anular, preferably circular, in the horizontal plane.

In this way by suitably programming the control box 51, it is possible to generate geometric criteria of movement of the bobbin 2 and/or the core 102 and of the pick-up head 15 that minimize the centering procedure.

The use of a circular path allows also to provide for a bobbin-carrier storage 11 of a rotating type that carries at least two stacks of bobbins. The stacks of bobbins are distributed angularly with their axes on a same ideal circular path with reference to the axis of rotation of the storage 11. In the case of only two bobbins 2, these are obviously diametrically opposite each other.

When all the sensors 50 detect the presence of the corresponding peripheral section of the bobbin 2 or of the core 102, then yes it is in perfect centering condition and the box 51 initiates the pick-up procedure.

According to one perfectioning, the reading takes place in conditions of closure of the jaws 115 and/or 515 of the pick-up head 15. In this way it is possible to prevent errors due to tolerances of the diameter of the bobbins 2 and/or cores 102.

In this case the control box is programmed in such a way to stop the pick-up head 15 in the position of detection of the centering and to control the clamping jaws 115 of the bobbin 2 or those that grip the cores 102 in position of closure. Then the reading process of the centering is carried out and when the centering is completed, the jaws are opened and the pick-up head 15 is brought in clamping position of the bobbin 2 or the core 102.

When the bobbin storage 11 carries stacks of bobbins, it is possible that the control box 51 keeps count of the number of bobbins 2 of each stack. In this case, programming the parameters relative to the axial dimensions of the bobbins in the control box, it is possible to adapt from time to time the vertical position of detection of the pick-up head 15, always taking the same to such a distance from the bobbin 2 on top of the stack, where the radius of operation of the sensors ends at an intermediate level between the two faces of said bobbin 2 on the top of the stack. This can be obtained both by raising the support plane of the bobbin-carrier storage 11, as well as more convenient for said construction by adapting the vertical position of detection of the pick-up head. The control box 51 will be equipped for example with a counter and with a suitable data processing program in which the axial dimension of the bobbins can be programmed and that keeps score of the number of bobbins picked-up from each stack, as well as of the code of the stack itself. The pick-up head 15 will therefore be approached from time to time in a dimension corresponding to the number of bobbins 2 picked-up from the corresponding stack as far as the vertical reading position of the centering is concerned., each time that the corresponding stack presents itself to the position of pick-up of a bobbin, that is in the pick-up station.

Alternatively, using the full bobbin 2 presence sensor 17, the reading position of the pick-up head 15 can be determined from the direct measurement by the pick-up head 15 of the level of the face turned towards the same of the bobbin 2 on the top of the stack in the pick-up station. This option can be used in the case that stacks of bobbins should be used that are not homogeneous with regards to the axial dimensions within the range of a stack itself.

When the bobbins are homogeneous with regards to the dimension in height it is possible to use the sensors 50 to replace also the sensor rings 17 and 19.

Obviously, instead of the sensors 50 of the photocell type it is possible to provide for other types of sensors this also depending on the topology of the material handled.

The sensors can also be arranged in different positions and this also dependent from their topology or it is possible to provide different types of sensors in different positions.

The movements of reciprocal alignment or centering of the bobbin and/or the core with the pick-up head can take place in both directions as indicated by the arrows F1 and F2 in Fig. 1 and can also be formed by steps of advancement of a preset amplitude. It is also possible that the steps are instead calculated for example thanks to additional information on the position of the bobbin and/or core and/or pick-up head.

With regards to the rotary type bobbin-carrier storage or stores 11, in the example illustrated, these are constituted by tables in form of a plane rotating around a vertical axis. These carry more stacks of full bobbins 2, each of the stacks being taken to the pick-up position, coinciding coaxially with the pick-up head 15, with a preset rotation 111 of the plane of the table. This one is driven by a motor 211 by means of a suitable transmission (not illustrated) and in a synchronized manner with the means of supply, or with the pick -up head 15.

Advantageously, the rotary plane 111 of the storage in form of a rotating table is suitable to house or is formed by a so-called pallet, facilitating considerably the operations of loading the storage 11. In particular the pallet has dimensions different from the ones of the CEE standards and substantially reduced, that is the 1200 mm of length and 800 mm of width. Each pallet can in this way house substantially diagonally offset two bobbins of diameter of 600 mm, like those customary used in the cigarette packing machines, or similar.

Claims

Supply unit of bobbins of material, in particular of bobbins of wrapping material in shape of a band and in cigarette packing machines, comprising:

a) a bobbin carrier storage (11) in which at least one bobbin is loaded;

b) a bobbin holder device (5) in a machine (1) using the bobbins (2);

c) a pick-up device (15) provided with a clamping device (115, 215) and able to transport a bobbin (2) from the bobbin carrier storage (11) to the bobbin holder device (5);

d) the pick-up device (15) being arrangeable in a preset pick-up station, in which a bobbin (2) of the bobbin carrier storage (11) is centered relative to the pick-up device (15) and is withdrawn from the carrier storage (11) by the clamping device (115, 215);

e) first means (21) for moving the bobbin carrier storage (11) relative to the pick-up device (15) arranged in the pick-up station, according to a first transversal direction of the axis of the bobbin (2) to bring the bobbin (2) in its centered position to the clamping device (115, 215) of the pick-up device (15) ;

f) second means (13, 14) for moving the pick-up device (15) relative to the bobbin (2) according to a path perpendicular to the first direction of movement of the bobbin carrier storage (11) and parallel to the axis of the bobbin (2) itself;

g) centering means (50, 51) comprising sensors (50) and a control box (51) for adjusting the centering of the bobbin (2) relative to the clamping device (115, 215) of the pick-up device (15) in the pick-up station, the said centering means (50, 51) control the activation and stop of the first means (21) for moving the bobbin carrier storage (11),

h) the clamping device (115,215) of the pick-up device (15) comprises at least two, preferably more radial jaws (115) able to overlap at least two diametrically opposite points or sections or more points or sections angularly distributed along the external perimeter of the bobbin (2) on the peripheral side of the same, the said jaws (115) being radially movable relative to a common axis parallel to the axis of the bobbin (2) itself from a radially inward receding clamping position to a non clamping position moved radially outward, characterized in that

i) the sensors (50) of the centering means (50, 51) are fitted on each jaw (115) and are able to detect the corresponding points or section of the peripheral side of the bobbin (2) or of the external peripheral edge and/or of the internal peripheral edge of the bobbin (2).
Supply unit according to claim 1, characterized by at least two pairs of sensors (50) to read at least two diametrically opposed points or sections of the external perimeter of the bobbin (2).
Supply unit according to claim 1, characterized by three sensors (50) distributed angularly equidistant and in such a manner to read the diameter of the external peripheral edge and/or of the internal peripheral edge of the bobbin (2).
Supply unit according to one or more of the preceding claims, characterized by the fact that the sensors (50) are constituted by photocells (50) with a maximum radius of operation such that the maximum level of reading is intermediate with regards to the thickness of the bobbin (2), a signal being therefore generated by the sensors (50) only when the bobbin, that is the external or internal peripheral edge of the same enters into the operative field of the photocell (50).
Supply unit according to one or more of the preceding claims, characterized in that the pick-up device (15) is movable according to a further direction (o) transversal to the one of moving towards away (V) from the bobbin (2) parallel to the axis of the bobbin (2) itself, the said further direction (o) intersects with the path (R) of motion of the bobbin (2) destined to bring the bobbin (2) in its centered position relative to the clamping device (115, 215) of the pick-up device (15) in the pick-up station, means (9) being provided for guidance and movement of the pick-up device (15) in the said direction (o) and the means (9) of motion being themselves driven by the control box (51) on hand of the signals emitted by the sensors (50).
Supply unit according to claim 5, characterized in that the path (R) of motion of the bobbin (2) destined to bring the bobbin (2) in its centered position is a circular one.
Supply unit according to one or more of the preceding claims, characterized in that:

the bobbin carrier storage (11) has a horizontal support plane (111) for at least one bobbin (2) and that can be rotated around a vertical axis external to the bobbin (2) itself and parallel to the axis of the bobbin (2);

wherein the pick-up device (15) is movable according to two directions perpendicular to each other and rectilinear (V, o), of which one (V) of axially moving towards and away from the bobbin (2) to be picked up and parallel to the axis of the bobbin (2) itself, whereas the other (o) is a horizontal rectilinear path that is oriented in such a way whereby the axis parallel to said path and intersecant with the common vertical axis of the radial clamping jaws (115) and one secant to the circular path (R) that the bobbin (2) carries out during the rotation of the bobbin (2) on the rotary bobbin carrier storage (11);

the correct centered position of the bobbin (2) relative to the clamping jaws (115) of the pick-up device (15) being provided at the point of intersection of the ideal circular path (R) of the axis of the bobbin (2) and the horizontal rectilinear path (o) of the common vertical axis (V) of the clamping jaws (115);

and the staggering of positioning of the bobbin (2) in the said correct centered position being detected by means of said sensors (50), the signals of which are processed by the control box (51) that drives the means (9, 13, 14) for moving the pick-up device and the means for moving the bobbin carrier storage (11) in the sense of defining the correct centered position of the bobbin (2) on the bobbin carrier storage (11) relative to the clamping jaws (115) of the pick-up device (15) as being the position, in which each sensor (50) reads the presence of the bobbin (2) in its field of operation.
Supply unit according to one or more of the preceding claims, characterized in that the bobbin carrier storage (11) carries at least one stack of coaxial bobbins (2).
Supply unit according to one or more of the preceding claims, characterized in that the bobbin carrier storage (11) carries more bobbins (2) side by side or more stacks of bobbins (2) side by side that are arranged with their central axes equidistant from the axis of the circular path (R) of movement in the pick-up station.
A method for the supply of bobbins using the supply unit according to any of the claims 1 to 9, characterized in that it comprises the following steps:

the axial movement of approach of the pick-up device (15) relative to the bobbin (2) in the pick-up station for bringing the clamping jaws (115) of the pick-up device (15) in a clamping position of the bobbin (2) is stopped in a intermediate position for detection and carrying out the centering of the bobbin (2) relative to the clamping jaws (115);

the clamping jaws (115) are closed in this intermediate position and the signals emitted by the sensors (50) pilot the control box (51) to drive the first means (21) for moving the bobbin carrier storage (11) to bring the bobbin (2) in a perfect centered position relative to the clamping jaws (115) of the pick-up device (15);

the clamping jaws (115) are opened and the pick-up device (15) is brought in a clamping position, in which the jaws (115) are closed again to clamp the bobbin (2).
A method according to claim 10, characterized in that

the bobbin (2) is moved in small steps in direction of the sensor (50) that has not detected the presence in its field of operation of the corresponding peripheral part of the bobbin (2);

the reading is repeated and the signals are analyzed anew;

according to the reply of the sensors (50), the opportunity of carrying out as the next step also or in alternative a step of movement of the pick-up device (15) is verified.
A method according to one of the claims 10 or 11, characterized by a repetition of intercalated steps between each other in the reading of the signals emitted by the sensors (50), in one or more steps of moving the bobbin (2), in the analysis of the results obtained by the movement by means of a new reading of the signals received from the sensors (50), in the processing of the eventual further successive movements of the bobbin (2), as well as the direction and amplitude of the step.
A method according to one or more of the claims 10 to 12, characterized by the reading of additional dimensions of the position of the bobbin (2) relative to the correct centered position of the bobbin (2).