Apparatus for transferring and rotating an object

An apparatus transferring and rotating an object from a retaining station to a releasing station along an annular transfer path, the object has a first orientation in the retaining station which is different from a second orientation in the releasing station; the apparatus includes: a stator having a revolution body provided with a lateral surface on which a first cam profile is formed; a rotor that is rotatable about a first rotation axis with respect to the stator; at least one retaining head of the object connected to the rotor, which has a retaining element coupled to the first cam profile which can be rotated about a second axis of rotation with respect to the rotor; and wherein the stator has a second cam profile and the transferring and rotating apparatus has at least a first annular guide disposed along the transfer path and the head has at least one first slide supporting the retaining element and is slidably coupled to the first annular guide, the first slide being connected to the rotor by way of a respective angular position variation mechanism coupled to the second cam profile to induce the sliding of the first slide into the first annular guide.

TECHNICAL FIELD

The present invention relates to an apparatus for transferring and rotating of at least one object, particularly of small dimensions, for example a base component for the production of an absorbent article, between two operating stations that allow changing the orientation of the object between the same stations. In detail, the present invention relates to a transfer and rotation apparatus included in a packaging machine for the realization of sanitary absorbent articles.

BACKGROUND

As is well known, sanitary articles, in particular baby diapers, sanitary napkins or incontinence products for adults comprise a layer of absorbent padding enclosed in a layer of non-woven fabric and a waterproof layer, for example polyethylene. These components are the basic elements of an absorbent article. In addition to these basic components mentioned above, the absorbent articles comprise further additional components (such as elastic bands, fecal barriers and side wings) which make the structure, as well as the realization, complex.

A known type of packaging machine for making sanitary absorbent articles comprises an advancing line of a continuous strip of impermeable material along which a plurality of operating units are disposed which feed the continuous web both of the basic components and of the additional components intended to complete the absorbent article.

Each operating unit comprises a processing apparatus that receives a component and processes the same component (for example by cutting the component into discrete lengths if the component is fed as a continuous strip to the processing apparatus) and a transferring and rotating apparatus that receives the component from the processing apparatus, when the processing has ended, and applies the component to the strip of impermeable material, picking up the component in a first orientation and releasing it in a second orientation, rotated with respect to the first orientation.

Generally, the transferring and rotating apparatus comprises a central drum which rotates around a central axis of rotation and supports, by means of a plurality of radially extending arms, respective suction retaining heads to hold the component during the transfer. Each suction retaining head can rotate further relative to the central drum itself to change the orientation of the component between a pickup station, in which the basic component is received by the transfer element, and a release station, in which the base component is released to a subsequent apparatus.

During the rotation of the central drum, the position of the suction retaining head with respect to a rotation axis of the drum itself is modified radially between a first radius, at the pickup station, and a second radius, at the release station, for varying the linear speed of the retaining head itself, and then accelerate or decelerate the components during the transfer from the pickup station to the release station.

In this way it is possible to pick up a succession of basic components from the pickup station spaced at a certain interval, commonly also called step or “pitch”, and deliver the same components in the release station spaced by a different interval.

The rotation of the radial arms with respect to the central drum, the rotation of the retaining heads with respect to the radial arms and the variation of the radial position of each retaining head are mechanically controlled by means of respective driving cams.

The variation of the radial position of each retaining head can cause excessive stresses in the retaining head, and then excessive wear of the same retaining head that may be subject to breakage or undesired malfunctions.

Furthermore, during a format change operation, i.e. during an operation that changes the packaging machine to vary the type of sanitary absorbent articles which are to be packaged, it is often necessary to modify the law of motion of the suction retaining heads to adapt this law of motion to a different size and/or location of the components that are treated.

Modification of the law of motion of the retaining heads requires the replacement of some mechanical components, typically at least the corresponding cams, and such replacement is particularly long and complex due to the positioning of the cams themselves towards the base of the transferring and rotating apparatus, which requires disassembly and subsequent assembly of numerous additional mechanical components and a step of configuration that is rather lengthy and requires the intervention of a skilled technician.

EP 2659869 A1 discloses an apparatus for transferring and rotating an object.

SUMMARY

The object of the present invention is to provide an apparatus for transferring and rotating an object, which is free from the drawbacks described above, and which, in particular, is simple and economical to produce.

A further object is to provide an apparatus for transferring and rotating an object that transfers and rotate an object reducing the possible wear of the mechanical components and which has therefore a longer operating life than the prior art.

According to the present invention, there is provided an apparatus for transferring and rotating an object, as claimed in the attached claims.

DETAILED DESCRIPTION

In this description, similar elements in common to the embodiments illustrated are indicated with the same numbering.

As shown inFIG. 9, with1is indicated in its entirety a packaging machine for the production of hygiene articles. The packaging machine1comprises a processing apparatus2which feeds to a retaining station4, in succession and along a processing path P1a plurality of objects3, in particular components or additional components for the construction of hygienic articles. Details on the processing apparatus2and the components for making sanitary articles have already been provided previously and will not be herein repeated.

The packaging machine1also comprises an advancing line5of a continuous strip (not shown) of impermeable material which receives in succession the objects3from a releasing station6and moves them along a feed path P2.

Note that the objects3have a first orientation in the retaining station4which is different from a second orientation in the releasing station6.

Assuming that each object has a longitudinal axis O, or an axis of prevalent development O, the first orientation is given by the arrangement of the longitudinal axis O with respect to the processing path P1and the second orientation is given by the arrangement of the longitudinal axis O with respect to the feed path P2.

In the retaining station4, the objects3have their longitudinal axis O parallel to the feed path P1, and are spaced apart by a distance D1while in the release station6the longitudinal axis O of each object3is perpendicular to the path of advancement P2and the objects3are rotated and spaced apart by a distance D2.

The packaging machine1comprises a transferring and rotating apparatus7for the transfer and the rotation of at least one object3from the retaining station4to the releasing station6along an annular transfer path T.

As shown in detail inFIGS. 1 to 8, the transferring and rotating apparatus7comprises a stator8(FIG. 6) comprising a revolution body24, provided with a lateral surface25, and a rotor9(FIGS. 1, 2, 3 and 7) rotatable about a first axis R1of rotation relative to the stator8.

The rotor9comprises at least one retaining head10of the object3connected to the rotor9, which retaining head10comprises a respective retaining element11rotatable about a second axis of rotation R2(FIG. 5) with respect to the same rotor9. The retaining head10receives the object3in the retaining station4from the processing apparatus2, and transfers the object3to the releasing station6of the advancing line5along the transfer path T rotating the object3from the first orientation to the second orientation during the rotation the rotor9.

The retaining element11is shaped such as to be able to cooperate with the object3. In the embodiment shown inFIGS. 1 to 7, the retaining element11is externally convex and presents surface openings11ato allow the retention and the transport of the object by means of air suction devices, known and not illustrated. In other words, the retaining head10is a retaining suction head.

The stator8includes a first cam profile12(FIG. 6) being realized in the side surface25and the retaining head10is provided with a corresponding first follower13, for example a roller, which cooperates and is coupled to the first cam profile12. The first follower13is suitable to cause the rotation of the retaining element11around the second rotation axis R2as a function of the relative position of the first follower13relative to the first cam profile12.

The stator8also comprises a second cam profile14, of which further details are in the following.

As shown inFIGS. 1 to 7, the transferring and rotating apparatus7comprises at least a first annular guide15arranged along the transfer path T and the retaining head10comprises at least a first slide16that supports the retaining element11and is slidably coupled to the first annular guide15.

The first slide16is connected to the rotor9by means of a respective variation mechanism17of the angular position of the retaining head10with respect to the rotor9, which variation mechanism17cooperates and is coupled to the second cam profile14to cause the sliding of the first slide16in the first annular guide15, as a function of the relative position of the variation mechanism17with respect to the second cam profile14.

The first annular guide15is fixed to the rotor9and is rotatable with respect to the stator8integrally with the rotor9.

The variation mechanism17oscillates with respect to a rotation pivot18, having a third rotation axis R3which is parallel to the first rotation axis R1of the rotor9. The variation mechanism17has a first end17awhich is provided with a second follower19, for example a roller as in the attached figures, suitable to be coupled to the second cam profile14, and a second end17bwhich is fastened to the first slide16.

Note that the variation mechanism17comprises a substantially triangular plate and that the rotation pivot18is placed at a vertex, the first end17aand second end17bof the variation mechanism17being located at respective ends of a respective first arm and second arm extending from the vertex.

The stator8also comprises a front wall22and the second cam profile14comprises a flat cam being realized by means of a groove of the front wall22.

The transferring and rotating apparatus7comprises a motor23(FIGS. 1 and 2), which is placed beyond a pedestal of the apparatus and is connected in known manner to the rotor9by means of drive gears.

The revolution body24of the stator8, shown in detail inFIG. 6, is so shaped as to be sphere-conic, i.e. it has a spherical surface that is tapered at the ends with an axis of symmetry which corresponds to the first rotation axis R1of the rotor9.

Note that the first cam follower13, which extends axially along a fourth rotation axis R4, is connected via a lever26, which has two portions which are inclined one another, to a rotation shaft41(FIG. 6) which extends between a first end, connected to the lever26itself, and a second end (not shown), to which is fastened the retaining element11. The rotation shaft41is rotatable with respect to the second rotation axis R2so that to every movement of the first follower13in the respective first cam profile12follows a corresponding rotation of the retaining element11about its own second rotation axis R2.

The second rotation axis R2of the retaining element11and the fourth rotation axis R4of the first cam follower13are incident to each other and incident also, in a point of incidence, to the first rotation axis R1of the rotor9.

This is due to the particular shape of the revolution body24and of the lever26, the former being of frustum-shaped type and the latter having portions inclined one to the other.

In detail, the revolution body24, the first cam profile12and the first follower13, the particular mutual arrangement between the first rotation axis R1of the rotor9, the second rotation axis R2of the retaining element11and the fourth rotation axis R4of the first follower13are of a known type as shown by the International application WO2014/167369 which is cited and incorporated herein without loss of generality.

As shown inFIG. 8, the rotor9may comprise, in particular, a body27, interposed between the revolution body24and the front wall22. The body27may be circular. The first annular guide15is interposed between the body27and the revolution body24.

More in detail, as shown inFIGS. 4 and 5, the first annular guide15comprises an external edge28, in particular having V-section, which is provided with two respective rolling surfaces28aand28bopposite to each other. The first slide16comprises a first pair of wheels29and a second pair of wheels30, being spaced from each other along the transfer path T, which are idly mounted on the first slide16such as to slide on the external edge28. The first pair of wheels29is downstream of the second pair of wheels30along the transfer path T. The wheels of each pair of wheels29and30are coaxially arranged in order to roll each along a respective rolling surface28aand28bof the external edge28of the first annular guide15.

In addition, the first annular guide15also includes an internal edge31, having a smaller distance than the external edge28with respect to the first rotation axis R1of the rotor9, which is also provided with two respective rolling surfaces31a,31bopposite to each other. The first slide16comprises, in addition, a third pair of wheels32which are idly mounted on the first slide16such as to slide on the internal edge31. The wheels of the third pair32are coaxial to each other and are arranged in order to roll, each, along a respective rolling surface31a,31bof the internal edge31.

The wheels of the third pair32are interposed between the first pair of wheels29and the second pair of wheels30along the transfer path T. The arrangement of the wheels of the first pair29, the second pair30, and the third pair32at the vertexes of a triangle facing towards the first rotation axis R1of the rotor9in which the wheels of the third pair32define a vertex, ensure a simultaneous sliding of the slide16both on the external edge28and on the internal edge31, and then an optimal stability of the first slide16during the sliding.

The first slide16comprises a respective bracket33on which the first pair of wheels29, the second pair of wheels30and the third pair of wheels32are fastened, the first pair of wheels29and the second pair of wheels30being fastened more outwardly with respect to the third pair of wheels32with respect to the first rotation axis R1of the rotor9.

Note in addition that the first slide16comprises a fastening pin34, which fastening pin34has a first end fastened to the bracket33and a second end secured to the second end17bof the variation mechanism17.

The fastening pin34is interposed between the first pair of wheels29and the second pair of wheels30along transfer path T, in such a way that the said second end17bis fixed in a substantially central position in the first slide16in order to ensure optimal sliding.

The transferring and rotating apparatus7also comprises a second annular guide35and it is noted that the revolution body24of the stator8is interposed between the first annular guide15and the second annular guide35.

The retaining head10also comprises a second slide36(FIGS. 4, 5, 6 and 7), which supports the retaining element11and is slidably coupled to the second annular guide35; in addition the retaining head10also comprises a supporting base37, in particular rectangular, at whose first opposite sides37athe first slide16and the second slide36are respectively fixed.

The second annular guide35is similar to the first annular guide15as well as the second slide36is similar to the first slide16.

A first pair of wheels38and a second pair of wheels39of the second slide36are then idly mounted on the second slide36to slide on an external edge44of the second annular guide35while a third pair of wheels40is idly mounted on the second slide36to slide on an internal edge45of the second annular guide35. The only difference between the first slide16and second slide36is given by the absence in the second slide36of the fastening pin34of the change mechanism17.

The second slide36comprises a respective bracket46on which are fixed the first pair of wheels38, the second pair of wheels39and the third pair of wheels40, the first pair of wheels38and the second pair of wheels39being fixed more outwardly with respect to the third pair of wheels40with respect to the first rotation axis R1of the rotor9, in a similar manner to what already said for the first slide16.

The bracket33of the first slide16and the bracket46of the second slide36are fixed laterally to first opposite sides37aof the supporting base37.

In this way, the supporting base37, the first slide16and the second slide36define a support carriage of the retaining element11which is slidable on the first annular guide15and on the second annular guide35.

As is shown in detail inFIG. 7, the support base37has a hole in order to house a rotation shaft41to which the retaining element11is fixed. The rotation shaft41extends axially along the second axis of rotation R2of the retaining element11and is fixed to the supporting base37via annular bearings that allow the rotation shaft41, integral with retaining element11, to be able to rotate with respect to the supporting base37.

As shown inFIG. 7, the retaining head10comprises a first protective wall42and a second protective wall43fastened to second opposite sides37bof the supporting base37, respectively downstream and upstream from the support base37along transfer path T. Protective walls42and43are configured to protect the first cam profile12from contaminants and particles, in detail each comprises a first portion that overlaps a side of the supporting base37band a second portion that overlaps the first cam profile12. For the attachment of the protective walls42and43to the supporting base37suitable fastening supports are present, among which the supports for the attachment of the protective wall43are external, shaped to “L” and indicated with47inFIG. 7.

Note that the transferring and rotating apparatus7shown in the Figures comprises a plurality of retaining heads10, in detail comprises seven different retaining heads, which are radially distributed about the first axis of rotation R1of the rotor9.

If we consider two successive retaining heads, namely a first retaining head which is downstream of a second retaining head along the transfer path T, it can be observed that the first retaining head and the second retaining head are able to be spaced from each other in a distanced position or in a near position depending on the relative position of the respective variation mechanisms with respect to the second cam profile14.

The first protective wall42and the second protective wall43of each support base37are fastened with an offset in a radial direction with respect to the first rotation axis R1of the rotor9so that, the first protective wall42of the upstream retaining head and the second protective wall43of the downstream retaining head are superimposed when two successive retaining heads are in a near position.

This is particularly evident inFIG. 7, in which three subsequent retaining heads10′,10″ and10′″ are represented, each identified with a respective apices for simplicity, of which the most downstream retaining head10′ is in a near position with respect to the central retaining head10″ and the central retaining head10″ is in a distanced position with respect to the most upstream retaining head10′″.

Note that the second protective wall43of the downstream retaining head10′ is superimposed on the first protective wall42of the central retaining head10″ while the second protective wall43of the central retaining head10″ is distanced and not superposed on the first protection wall42of the most upstream retaining head.

In use, when the motor23puts the rotor9in operation, all the retaining heads10with which the transferring and rotating apparatus7is fitted are all at the same distance and the rotation pivot18of the variation mechanism17of each retaining head10moves at the same angular speed of the rotor9. The second follower19moves, however, engaging the second cam profile14of the front wall22, which is eccentric with respect to the first rotation axis R1of the rotor9, and then the variation mechanism17periodically rotates by a certain angle with respect to the rotor9as a function of the relative position of the second follower19with respect to the second cam profile14. During the rotation of the rotor9, the second end17bof the variation mechanism17moves then periodically forward and consequently drags forward also the first slide16, integral with the variation mechanism17by means of the fastening pin34.

It follows that, cyclically, each retaining head10is accelerated and subsequently decelerated. Considering two successive retaining heads then the distance between them can be modified during rotation of the rotor9about the first rotation axis R1and therefore the distance D1(pickup step) between two successive retaining heads at the retaining station4, can be different from the distance D2(release step) between two successive retaining heads at the releasing station6.

The sliding of the first slide16also drags the carriage, defined by the first slide16itself, the support base37and the second slide36, and the carriage in turn drags the rotation shaft41and the retaining element11, that moves integrally to the carriage. Since one end of the rotation shaft41is connected to the first follower13which moves during the rotation of the rotor9by engaging the first cam profile12of the revolution body24, which is also eccentric with respect to the first rotation axis R1of the rotor9, the retaining element11fixed to the other end of the rotation shaft41rotates with respect to the second rotation axis R2as a function of the position of the first follower13in the first cam profile12.

The first cam profile12and the second cam profile14are shaped in such a way that each retaining head10can be accelerated before being rotated by 90°.

Owing to the retaining head10connected to the rotor9via a respective variation mechanism17of the angular position and owing to the support of the retaining element11by means of a first slide16slidably coupled to a first annular guide15, which rotates integral to the rotor9, the retaining head10is supported in a sturdy manner and also is driven with stable movements to transfer and rotate an object, i.e. a component of a hygienic article.

It is added that the presence of both the first annular guide16and the second annular guide36, on which the second slide35slides, allows a carriage defined by the support base37, by the first slide16and by the second slide36, to slidably support the rotation shaft41, to which the retaining element11is fixed, avoiding possible vibrations to the retaining element11itself during its rotation about the second axis of rotation R2. Consequently it is guaranteed stability in the transport of components of sanitary items, usually lightweight and easily deformable.

The specific arrangement of the revolution body24between the first annular guide16and the second annular guide36and the arrangement of the second cam profile14in a front wall22of the stator8which is directed, in use, toward the operator side, allows a simple variation of the picking up step and the release step where it is necessary a format change.

It is possible to modify a format of the transferred component by changing the number of retaining heads10, since the retaining elements11can consequently be replaced, to change their shape and/or size. By only replacing the front wall22in which the second cam profile14is obtained, it is possible that an operator changes the law of motion of any new retaining heads without difficult setup configurations, such as to decide acceleration and/or deceleration areas different from the previous format.