Machine for removing a lid from a container and the related plant

A machine for removal and extraction of a lid for containers includes: a centering element, for aligning the machine above the container; a gripping device for acting upon a contained lid, being capable of disengaging the lid from the container and holding the same lid; a first device for moving said gripping device along a vertical axis, between first and second positions, proximal to, and away from said centering element and a support structure, fixed to said centering element, for supporting said first device. The gripping device takes first and second operating configurations, wherein it does not act upon said lid, and wherein it does act upon a protruding portion of the lid. The centering element has an abutment portion to abut against an upper container edge, and to prevent the container from moving, without exerting any force upon said edge.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 National Stage of International Application No. PCT/IB2018/054002, filed Jun. 5, 2018, which claims priority to Italian Patent Application No. 102017000062313 filed Jun. 7, 2017. The disclosure of each of the above applications is incorporated herein by reference in its entirety.

The present invention relates to an automatic machine capable of removing a lid from a container, which machine can be comprised in a plant for the production of fluids, such as paints.

The machine according to the present invention allows removing and extracting a lid from a container; in particular, the machine is suitable for containers having an outer top wall, partially annular, defining an aperture. In its portion of the inner peripheral edge of the top wall, the container defines an annular cavity open at the top adapted to receive the bottom surface of an annular channel open at the top comprised in the lid or cover to be removed. In its turn, the lid includes a portion protruding out of said cavity, through which the lid can be disengaged from the top wall of the container.

Manual systems for opening a lid from a container are known which are adapted to separate, at least partly, the lid from the container. Such systems exert a force upon said outer top wall of the container. This operation may cause deformation of the top wall of the container, with the risk of irreparably damaging said wall, so that sealing with the lid will no longer be ensured.

Manual mechanical systems are also known which are adapted to separate a metal lid from a container and allow complete removal thereof.

Such a system exerts a thrust force upon the outer top wall of the container, which force, though apparently distributed over most of the edge, is nevertheless considerable. This force will be proportional to the degree of connection between the lid and the container.

In this case as well, the force exerted by the system upon the outer top wall of the container may cause damage to the latter, thus preventing reuse thereof. This latter solution is exclusively applicable to metal lids; in fact, complete removal of the lid from the container requires interaction between the lid and a permanent magnet.

Therefore, the solution known in the art does not allow for complete removal of the lid from the container.

Manual mechanical systems are known from document US2016332857 which can open a container and remove the lid. However, a drawback of the solution described therein is that it causes deformation of the container, since a considerable force is exerted upon the outer top wall, which force may break and/or irreparably damage the container. Such a mechanical system does not include container holding systems for preventing the container from moving during the lid removal operations.

The present invention aims at solving these and other technical problems suffered by the prior art by providing an automated machine for removal of a lid from a container, which can act upon metal and/or plastic containers without exerting a force upon the outer top wall of the container that might cause deformation thereof and jeopardize the integrity and/or prevent subsequent reuse of the container.

One aspect of the present invention relates to a machine having the features set out in the appended claim1.

A further aspect of the present invention relates to a system having the features set out in claim10.

Further auxiliary features of the machine and/or plant are set out in the appended dependent claims.

With reference to the above-listed drawings, the machine for removal of a lid “L” from a container “C” is designated as a whole by reference numeral2.

Machine2is suitable for removal and extraction of a lid “L” for paint and/or dye containers or cans “C”.

Said container “C” and said lid “L” have the technical and structural features previously described in the present description. Lid “L” is also known in the industry as “pressure lid”. This type of lids coupled to containers are capable, at least in some embodiments thereof, of ensuring a hermetic seal.

Machine2according to the present invention comprises: a centring element3, adapted to allow properly aligning machine2above container or can “C”. Said centring element3allows machine2to be correctly positioned above container “C” prior to removal and extraction of lid “L”.

Machine2comprises a gripping device6. Said gripping device6is adapted to selectively act upon at least two points of a lid “L” placed on container “C”. Preferably, said gripping device6is adapted to act upon a lid “L” when the latter is closing a container “C”. Preferably, said gripping device6is adapted to selectively act upon a portion of lid “L” protruding out of a cavity comprised in container “C”, in which an annular channel open at the top, comprised in lid “L”, is positioned.

Said gripping device6is capable of both disengaging lid “L” from container “C”, thus removing it, and holding the same lid “L”, so that it can be extracted. Preferably, said gripping device6is adapted to remove the annular channel of lid “L” from the cavity comprised in container “C”.

Machine2according to the present invention further comprises a first moving device5.

Said first moving device5is adapted to move said gripping device6. The movement of gripping device6preferably occurs along a vertical axis “Z”. The movement occurs between at least one first position, proximal to said centring element3, in which said gripping device6is proximal to said centring element3, and at least one second position, away from said centring element3. Such movement made by the first moving device5allows moving gripping device6towards and away from container “C”, thus allowing gripping device6to interact with the lid “L” and/or remove the lid “L” by extracting it from container “C” and/or moving it away from the same container “C”.

Machine2further comprises a support structure4. Said support structure4is fixed to said centring element3. Said support structure4is adapted to support said first moving device5.

Said gripping device6is adapted to take a first operating configuration, wherein it is non-influential upon a protruding portion of lid “L”, since it does not act upon said protruding portion of lid “L”; and a second operating configuration, wherein it is adapted to act upon a protruding portion of the annular channel open at the top, comprised in lid “L”.

Said centring element3comprises an abutment portion32. Said abutment portion32is adapted to abut against an upper edge of the outer top wall of container “C”, hereafter defined as outer top wall. The same abutment portion32is adapted to prevent container “C” from moving, in particular while switching between the different operating configurations of machine2, and in particular while switching between the different operating configurations and/or positions of gripping device6, without exerting any pressure force upon said outer top wall of container “C”, in any operating configuration or spatial arrangement of gripping device6.

Machine2according to the present invention exerts no voluntary forces upon the edge of the outer top wall of container “C”.

In a preferred embodiment of machine2according to the present invention, said first moving device5comprises: a connection structure52, to which gripping device6is fixed; a first actuator device54, of the linear type, adapted to move said connection structure52along said vertical axis “Z”.

In a preferred embodiment of machine2according to the present invention, said gripping device6in turn comprises: at least two gripping elements62. Each gripping element62is adapted to selectively act upon one protruding portion of lid “L”.

Said gripping device6further comprises at least one support element63. To said support element63, at least two gripping elements62are operationally connected.

Said gripping device6further comprises at least one second moving device64.

Said second moving device64is adapted to move said at least two gripping elements62between the different operating configurations of gripping device6. In particular, said moving device64is adapted to move said gripping device6, and in particular said gripping elements62, between a first operating configuration, in which said gripping elements62are not adapted to act upon said lid “L”; and a second operating configuration, in which said gripping elements62are adapted to act upon a protruding portion of the annular channel open at the top of lid “L”.

In a preferred embodiment of machine2, the second moving device64comprises a second actuator device642. Said second actuator device642is preferably of the linear type.

Said second moving device64further comprises a driving element644.

Said driving element644is adapted to act upon said gripping elements62.

During its linear movement, said second actuator device642acts, through said driving element644, upon said gripping elements62, allowing said gripping elements62to selectively take either said first operating configuration or said second operating configuration. Preferably, said driving element644is shaped in such a way as to simultaneously act upon all gripping elements62.

In a preferred embodiment of machine2according to the present invention, each gripping element62comprises a coupling portion623.

Said coupling portion623has a shape complementary to the shape of the protruding portion of lid “L”. In particular, said protruding portion of lid “L” can at least partly be housed in said coupling portion623. In particular, said protruding portion of lid “L” is housed, at least partly, in said coupling portion623when gripping device6is in said second operating configuration.

Said coupling portion623is adapted to at least partly house, inside of it, said protruding portion of lid “L”. In particular, in the second operating configuration of gripping device6, coupling portion623houses, at least partly, said protruding portion of lid “L” while preferably exerting a force thereupon.

In general, said gripping device6is adapted to exert a thrust force upon said protruding portion of lid “L”, thereby deforming said annular channel open at the top comprised in lid “L”, without exerting any force upon said container “C”; therefore, the thrust force exerted by gripping device6will not deform container “C” in any way. In particular, in the second operating configuration, said gripping device6exerts such a thrust force as to deform said annular channel of lid “L”, thus decoupling the same lid “L” from container “C”.

In general, the force exerted upon lid “L” by gripping device6preferably has at least two components, each one having a direction perpendicular to said vertical axis “Z”. In particular, each gripping element62will be able to exert a force along a direction perpendicular to said vertical axis “Z”. Therefore, the greater the number of gripping elements62, the greater the force components applied onto lid “L” and having a direction perpendicular to said vertical axis “Z”. The direction and/or sense of the force of gripping elements62will be mutually different.

In a preferred embodiment of gripping device6, said gripping element62comprises a first matching portion625. The first matching portion625of gripping element62is acted upon by said driving element644.

The action upon the first matching portion625exerted by said driving element644, the latter being pushed by the second actuator device642, allows gripping element62to switch between said first operating configuration and said second operating configuration, and vice versa.

In a preferred embodiment of machine2according to the present invention, said gripping element62and said second moving device64are so made that the thrust action exerted along said vertical axis “Z” upon the first matching portion625of gripping element62by the second actuator device642, through said driving element644, is transformed into a substantially straight movement of coupling portion623along an axis perpendicular to said vertical axis “Z”.

In one possible embodiment, said driving element644acts, as it moves along vertical axis “Z”, upon the first matching portion635, which corresponds to the outer face of gripping element62. Said matching portion635comprises an inclined portion, so that the interaction with said driving element644will vary during the vertical movement of driving element644, achieved through said second actuator device642. For example, said matching portion635is configured in a manner such that during the downward movement of driving element644the action exerted upon gripping element62by the same driving element644will increase, and vice versa.

On the contrary, said coupling portion623is located on the inner face of gripping element62, facing towards lid “L”.

In a preferred embodiment, said driving element644is a ring adapted to act upon a plurality of gripping elements62, the latter being arranged along a circumference, preferably angularly equidistant from each other.

In an alternative embodiment, said gripping element62and said second moving device64are so made that the thrust action exerted along said vertical axis “Z” upon the first matching portion625of gripping element62by the second actuator device642, through said driving element644, is transformed into a substantially rotary movement of coupling portion623about an axis perpendicular to said vertical axis “Z”.

In the preferred, though exemplary and non-limiting, embodiment of machine2according to the present invention, said support element63comprises a plurality of housings631.

In each one of said housings631, at least one elastic element632is housed.

Each elastic element632is adapted to exert a thrust force against a corresponding gripping element62, with which the elastic element632is associated.

In particular, elastic element632is adapted to interact with a hooking portion622of gripping element62, with which it is associated.

The thrust force exerted on said gripping elements62, and in particular on hooking portions622, by elastic elements632is such as to bring gripping device6, and in particular gripping elements62, into the first operating configuration.

Each elastic element632is inserted, at a first end thereof, into said housing631comprised in support element63, and, at a second end thereof, opposite to the first one, is adapted to act against said hooking portion622.

In general, said hooking portion622of gripping element62is adapted to connect said gripping element62to said support element63through a corresponding elastic element632, thereby allowing gripping element62to be moved between the different operating configurations.

Preferably, said elastic element632comprises a spring and a removable fixing element. Said spring is arranged coaxial and concentric to said fixing element, surrounding a central portion thereof. A first end of the fixing element is adapted to be removably fixed into said housing631, e.g. by screwing. The opposite end of said fixing element is inserted in a connection portion624, e.g. a housing, comprised in hooking portion622. Said connection portion624is shaped in such a way as to define a housing in which one end of said fixing element of the elastic element632is inserted, thus retaining it. Preferably, the end of said fixing element of elastic element632, inserted in connection portion624, comprises a head adapted to interact with said connection portion624, so that it will be prevented from coming out. Said head of the fixing element of elastic element632preferably comprises a coupling element to be coupled to a suitable wrench for tightening said fixing element of elastic element632.

Said elastic element632, e.g. in the above-described embodiment, can be removed from housing631and decoupled from hooking portion622of gripping element62, e.g. the fixing element can be removed from connection portion624. In this embodiment of elastic element632and gripping element62, the latter can be replaced and/or removed, e.g. for maintenance and/or in order to adapt gripping element62to the conformation of the protruding portion of lids “L” to be removed. It is therefore possible to replace gripping elements62with other gripping elements having an appropriately shaped coupling portion623, according to the shape and/or material of the protruding portion of lid “L”.

Each elastic element632is adapted to bring the gripping element62into its first operating configuration upon completion of the action exerted by driving element644upon the same gripping element62, and in particular upon said first matching portion625.

Said elastic element632, e.g. the coil-spring component, is subject to deformation when gripping element62is in its first operating configuration, in particular when driving element644is acting upon gripping element62.

Preferably, following the movement of gripping device from the first operating configuration to the second operating configuration, each gripping element62comes in mechanical abutment with said support element63. In particular, a second matching portion626of gripping element62comes in abutment with a stop portion630comprised in support element63, thereby preventing any further movement of gripping element62.

Said stop portion630is adapted to define the travel of said gripping element62, in particular the achievement of said second operating configuration, following the movement caused by the second moving device64.

In a preferred, though exemplary and non-limiting, embodiment of machine2, when gripping device6switches from the first operating configuration to the second operating configuration, said second actuator device642is activated and moves, preferably extends, along said vertical axis “Z”. The movement of the second actuator device642involves an equal movement of driving element644. The movement of driving element644causes a movement of gripping elements62as indicated above, in particular under the action exerted by driving element644upon the first matching portions625of gripping elements62. The movement of gripping elements62causes compression of elastic elements632. The movement of gripping elements62stops when gripping elements62, and in particular the second matching portions626, abut against said stop portion630of support element63.

The movement of gripping elements62allows coupling portions623to act upon the protruding portion of lid “L”.

Conversely, when the gripping device switches from the second operating configuration to the first operating configuration, said second actuator device642is activated and moves, preferably contracts, relative to said vertical axis “Z”. The movement of the second actuator device642involves an equal movement of driving element644. The movement of driving element644reduces the action exerted by driving element644upon gripping elements62, and in particular upon the first matching portions625.

The reduction of the action exerted upon gripping elements62by the driving element allows elastic elements632to extend. The extension of elastic elements632allows exerting a force upon said gripping elements62, which are then moved back into their first operating configuration.

The movement of gripping elements62causes coupling portions623to be decoupled from the protruding portion of lid “L”. In this condition, gripping elements62, and in particular coupling portions623, are no longer acting upon the protruding portion of lid “L”.

A preferred embodiment of machine2according to the present invention comprises a plurality of gripping elements62, e.g. twelve.

Said gripping elements62are rigid structures, e.g. made of metal or very hard plastic material. Gripping elements62are angularly equidistant from each other, in order to distribute the action evenly onto the outer protruding portion of lid “L”.

In the preferred embodiment of machine2according to the present invention, said first moving device5and said second moving device64are completely independent of each other, since they can be activated autonomously. In fact, in a first operating configuration machine2is adapted to extend said first moving device5, while keeping said second moving device64contracted, e.g. as shown inFIG. 1A. In a second operating configuration, machine2is adapted to extend said first moving device5, while also extending said second moving device64, e.g. as shown inFIG. 1B. In a third operating configuration, machine2is adapted to contract said first moving device5, while extending said second moving device64, e.g. as shown inFIG. 1C. In a fourth operating configuration, machine2is adapted to contract said first moving device5, while also contracting said second moving device64.

In this embodiment of machine2it is possible to prevent a pressure force, caused by an extension of a moving device (5,64), from being exerted upon container “C”, while nevertheless allowing the removal of lid “L”.

Moreover, with this embodiment of machine2it is possible to move lid “L” away from container “C” after opening container “C”, while possibly holding lid “L”.

Said first actuator device54is preferably a pneumatic actuator. In an alternative embodiment, said first actuator device54is of the hydraulic type.

Said second actuator device642is preferably a pneumatic actuator. In an alternative embodiment, said second actuator device642is of the hydraulic type.

In general, said stop portion630also abuts on an edge of lid “L”, so that said gripping element62can effectively act upon the protruding portion of lid “L”, deforming the annular channel open at the top comprised in the same lid “L”.

In one possible embodiment, said support structure4preferably comprises: tubular elements, connected to said centring element3; and a plate, whereon said first actuator device54is fixed. Said tubular elements are also fixed to said plate.

Said support structure4is capable of keeping said abutment portion32of centring element3at a predefined distance from the first actuator device54. Support structure4prevents that the movement of the elements comprised in machine2might cause the application of a compression force onto the edge of the outer top wall of container “C”, whereon said centring portion32is made to rest. Preferably, the movements that involve an actual application of force onto lid “L”, such as to cause it to be decoupled from container “C”, are exerted during downward movements of the moving devices (5,64). The conformation of gripping device6is such that during said movements no voluntary force will be applied onto said outer top wall of container “C” which may possibly cause deformation of the edge of container “C” itself. Preferably, the movements that involve an actual application of force onto lid “L”, such as to definitively separate it from container “C”, are exerted during upward movements of the moving devices, and in particular of said first moving device5.

This type of force, intended to ensure the actual separation of lid “L” from container “C”, is normally less than the force required for decoupling lid “L” from container “C”. In this case as well, therefore, any force transmitted to the outer top wall of container “C” will be very weak, and certainly insufficient to cause the same wall to undergo any deformation.

Furthermore, since said abutment portion32of centring element3has a circular shape, such as to abut on the entire edge of the outer top wall of container “C”, any involuntary forces that can be transmitted to the outer top wall of container “C” are equally distributed, thus further reducing the risk that any involuntary force transmitted to the outer top wall of container “C” might cause such a compression of the same wall that might lead to deformation thereof.

Said support structure4and said centring element3define the transversal extension of machine2. The first moving device and gripping device6lie within the structure defined by the same support structure4and by centring element3.

In one possible embodiment, said connection structure52preferably comprises a plurality of columns522and a plate521.

Said plate521constrains the mobile portion of the first actuator device54to the fixed portion of said second actuator device644.

At one end, said columns522are fixed to said plate521. To the opposite end of said columns522, said support element63is fixed, which comprises a plurality of housings631in which said elastic elements632are housed.

To the mobile portion of the second actuator element642, said actuator element644is fixed, so that it can be moved relative to said support element63and said gripping elements62.

In general, machine2can be positioned above container “C” manually, wherein an operator positions machine2above container “C” either manually or by means of a servomechanical system. Once machine2has been positioned and properly centred on the container, the same machine is activated in order to separate lid “L” from container “C” and then open said container.

In a more automated embodiment, machine2can be positioned above container “C” automatically, by appropriately controlling a moving device16connected to the same machine2. Said moving device16can position and centre machine2on container “C” in order to activate the same machine2, preferably automatically, and separate lid “L” from container “C” and possibly hold lid “L”, thus definitively removing lid “L” from container “C”.

Machine2according to the present invention is particularly suitable for inclusion in a plant1for dyeing products, such as paints.

In general, a plant1for dyeing products comprises: at least one processing station12, adapted to process dyeing products contained in a container “C”; and at least one moving device14.

Said moving device14is adapted to move one or more containers “C” from and/or to a processing station12.

Said moving device14may be a series of rollers and/or a conveyor belt, or other moving devices capable of moving at least one container “C” along a horizontal axis.

Said at least one processing station12may be a dosing station and/or a sampling station and/or a mixing station.

Machine2can be included in system1either upstream or downstream of a processing station12.

In one possible embodiment of system1according to the present invention, machine2is placed in proximity to the inlet of a processing station12.

System1further comprises at least one moving device16adapted to move said machine2.

In general, said machine2can be moved by means of a moving device16. Said moving device16is at least capable of moving said machine2along a vertical axis “Z”.

Said moving device16allows machine2to be positioned above container “C”.

In a preferred embodiment, said moving device16is a manipulator, e.g. an articulated arm, having at least one degree of freedom.

FIG. 1Ashows, in a perspective view, machine2according to the present invention placed above a container “C”. Centring element3allows machine2to be configured at best, while also positioning abutment portion32on the outer top wall of container “C”. Machine2shown inFIG. 1Ais in a first operating configuration. Said first moving device5, and in particular said first actuator device54, is configured in such a way as to position said gripping device6in the first position proximal to said centring element3.

The second moving device64is prearranged in such a way as to set said gripping elements62in a first operating configuration, in which they do not act upon said lid “L”. In fact, driving element644is in a raised position.

In this configuration, coupling portions623of the various gripping elements62do not interact with the protruding portion of lid “L”. Moreover, said stop portion630abuts against lid “L”.

In the drawing one can also clearly see the substantially vertical development of machine2according to the present invention. Machine2also looks very compact, since it has substantially the same dimensions as the illustrated container “C”.

From this figure one can understand how support structure4keeps the first actuator device54, and in particular the fixed portion thereof, at a predefined distance from said abutment portion32of centring element3. This prevents any compression forces from being applied onto the edge of the outer top wall of container “C”.

FIG. 1Bshows, in a perspective view, machine2according to the present invention placed above a container “C”. Machine2shown inFIG. 1Bis in a second operating configuration.

From a comparison betweenFIG. 1BandFIG. 1Ait emerges that also in this operating configuration of machine2said first moving device5keeps said gripping device6in the first position, proximal to said centring element3.

The second moving device64, on the contrary, is prearranged in such a way as to set said gripping elements62in the second operating configuration, in which they act upon a protruding portion of lid “L”. In fact, said driving element644is in a lowered position.

In the second operating configuration, said coupling portions623of gripping elements62interact with the protruding portion of lid “L”. In particular, at least a part of the protruding portion of lid “L” is housed in coupling portion623of each gripping element63.

This figure highlights one possible embodiment of the second moving device64in order to allow driving element644to be moved along said axis “Z” through the movement of said second actuator device642.

FIG. 1Cshows, in a perspective view, machine2according to the present invention placed above a container “C” in a third operating configuration.

In the third operating configuration of the machine, compared with the one shown inFIG. 1B, said abutment portion32still abuts on the outer top wall of container “C”; the first moving device5, and in particular said first actuator device54, is configured in such a way as to position said gripping device6in the second position, away from said centring element3. In comparison withFIGS. 1A and 1B, in fact, one can see that gripping device6, and more visibly the second actuator device642, has come nearer to the first actuator device54. Moreover, gripping elements62and support element63have moved away from abutment portion32of the centring element3. Therefore, gripping device6has moved away from container “C”.

During the transition from the second configuration, shown inFIG. 1B, to the third configuration of machine2, it is clear that lid “L” has been removed from container “C”.

Support structure4, being rigid, prevents the movements made by the first moving device5and/or by the second moving device64from translating into the exertion of a compression force upon the edge of the outer top wall of container “C”, whereon said abutment portion32of centring element3abuts.

FIG. 2Ashows the machine ofFIG. 1Ain a front view. The machine, in the first operating configuration, is positioned on container “C”. In this image it is visible that the first moving device5and gripping device6extend along a vertical axis “Z”.

In this image, a plurality of gripping elements62, in particular hooking portions622, are visible. The image shows driving element644adapted to act upon said gripping elements62.

FIG. 2Aalso shows the conformation of the support structure4to which said centring element3is connected. The sameFIG. 2Aclearly shows how said first moving device5puts said gripping device6into the first position proximal to said centring element3, and that said second actuator device642is in the configuration in which it does not push said driving element644downwards.

FIG. 2Bshows the machine ofFIG. 1Ain a sectional front view according to the vertical plane B-B. The machine is placed on container “C”, so that abutment portion32is on the outer top wall of container “C”. Stop portion630lies on lid “L”, matching therewith.

From this figure it emerges that said support element has a circular shape, around which said gripping elements62are arranged.

Also said driving element644has a circular shape, and surrounds said plurality of gripping elements62.

FIG. 2Ballows understanding how the second actuator device642, and in particular the fixed portion thereof, is fixed to said plate521, from which columns522extend, to opposite ends of which said support element63is fixed. Through said connection structure52, the first actuator device54is able to move said gripping device6.

Said driving element644is fixed to the mobile part of the second actuator device642.

In the drawing also housings631are visible, each one of which houses an elastic element632. Said elastic element632is constrained to said hooking portion622of gripping element6, since one end thereof is within connection portion624.

Elastic element632is in an extended configuration, exerting a thrust force upon said gripping element62to move it away from the same support element63.

FIG. 3shows a detail of gripping device6of the machine ofFIG. 2B. SaidFIG. 3shows hooking portion622and coupling portion623. This figure shows gripping device6in its first operating configuration, in which coupling portion623does not act upon the protruding portion of lid “L”.

This figure also partially shows the first matching portion625and the second matching portion626.

The figure also shows stop portion630abutting against lid “L”. Abutment portion32of centring element3abuts on the outer top wall of container “C”.

In the first operating configuration of gripping device6, every spring or elastic element632is extended, thus pushing the corresponding gripping element62; while the fixing element of each elastic element632abuts against connection portion624, and in particular against the bottom of the housing.

FIG. 4Ashows the machine ofFIG. 1Bin a front view. The machine is in the second operating configuration, in which gripping device6is in the second operating configuration, interacting with lid “L”. In particular, said coupling portion623houses, inside of it and at least partly, the protruding portion of lid “L”.

In the second operating configuration of gripping device6, said driving element644is moved by said second actuator device642, thus acting upon said plurality of gripping elements62.

Said centring element3rests, through said hooking portion32, on container “C”. During the transition between the first operating configuration of machine2and the second operating configuration, and in particular from the first operating configuration to the second operating configuration of gripping device6, no pressure force is exerted upon container “C”.

FIG. 4Bshows the machine ofFIG. 1Bin a sectional front view according to the vertical plane B-B.

Also in this operating configuration, machine2is placed on container “C”, so that abutment portion32lies on the edge of the outer top wall of container “C”. Stop portion630lies on lid “L”, matching therewith.

Said second actuator device642is in the configuration in which it pushes said driving element644, causing the same driving element644to act upon said plurality of gripping elements62. By pressing against said gripping elements62, the latter are moved and drawn closer to each other. In particular, the movement of driving element644along vertical axis “Z” allows each gripping element62to make a movement along an axis perpendicular to said vertical axis “Z”, radially to lid “L”. In particular, driving element644, as it moves, acts upon said first matching portion625of the various gripping elements62.

Following the movement made by the second moving device64, each elastic element632is compressed by the same gripping elements62, which approach support element63. As they approach support element63, gripping elements62abut, through said second matching portion626, against said stop portion630.

FIG. 5shows a detail of gripping device6of the machine ofFIG. 4B, in which hooking portion622and coupling portion623are visible.FIG. 5shows gripping device62in its second operating configuration, in which coupling portion623acts upon lid “L”.

This figure also partially shows the first matching portion625, whereon said driving element644abuts, and the second matching portion626, which abuts against said stop portion630.

The figure also shows that stop portion630abuts against lid “L”; that abutment portion32of centring element3abuts on the edge of the outer top wall of container “C”; and that the protruding portion of lid “L” is inserted in the housing defined by said coupling portion623.

In the third operating configuration of machine2, gripping device6continues to interact with lid “L”. The movement made by the first moving device5, which brings said gripping device6into the second position, distant from said centring element3, allows lid “L” to be definitively separated from container “C”.

Said centring element3and said support structure4ensure that, during the transition between the second operating configuration and the third operating configuration of machine2, and in particular from the first position to the second position of gripping device6, no voluntary pressure force will be exerted upon the outer top wall of container “C”.

In this third operating configuration, machine2has removed lid “L” from container “C”, without exerting any compression forces upon container “C”. Moreover, in this third operating configuration machine2is able to hold lid “L” once it has been definitively separated from container “C”.

FIG. 6Bshows the machine ofFIG. 1Cin a sectional front view according to the vertical plane B-B. The machine is placed on container “C”, so that abutment portion32lies on the outer top wall of container “C” and stop portion630still lies on lid “L”, matching therewith.

Said second actuator device642is still in the configuration in which it pushes said driving element644, causing the same driving element644to act upon said plurality of gripping elements62. Each elastic element632continues to be compressed by the same gripping elements62approaching support element63.

Although it is far from container “C”, gripping device6is able to hold lid “L” even when it has been separated from container “C”.

The first actuator device54has moved gripping device6, bringing it into said second position, so that lid “L” can be separated from container “C”.

FIG. 7shows a detail of the gripping device of the machine ofFIG. 6B, wherein hooking portion622and coupling portion623are clearly visible. This figure shows that gripping device6is in its second operating configuration, even though gripping device6is in the second position, away from centring element3. In this operating configuration of machine2, coupling portion623continues to act upon lid “L”, in particular by interacting with said protruding portion, even though lid “L” has been definitively separated from container “C”.

InFIG. 7one can see how the driving element acts upon the first matching portion625. Said gripping element62abuts, through said second matching portion626, against said stop portion630of support element63. The figure also shows that stop portion630still abuts against lid “L”.

Abutment portion32of centring element3still abuts on the outer top wall of container “C”. In the figure it is clearly visible that said elastic element632remains compressed. In particular, it is visible that the spring is compressed because gripping element62is being pushed by driving element644. The fixing element of elastic element632no longer abuts against connection portion624, and in particular in the housing.

FIG. 8shows, in a schematic manner, a plant1comprising machine2for removal of a lid “L” from a container “C” according to the present invention.

Said moving means14may be a conveyor belt or a series of rollers.

The container is in proximity to a processing station12, adapted to perform an operation on container “C” and/or on the content of container “C”.

Machine2is placed on container “C”. The illustrated machine2is in the third operating configuration, in which lid “L” has been removed from container “C”.

Machine2is adapted to rest on container “C”. The same machine2is moved by means of a moving device16, shown as an arm, which can move the entire machine2at least along a vertical axis “Z”.

Machine2according to the present invention is capable of removing a lid “L” without exerting any voluntary compression forces upon the outer top wall of container “C” on which lid “L” has been applied.

Machine2according to the present invention, since it comprises a centring element3adapted to centre machine2while retaining container “C” and a gripping device6capable of removing lid “L”, does not exert any voluntary thrust forces upon the outer top wall of container “C”, which wall defines the aperture on which lid “L” to be removed has been positioned.

Gripping device6, and in particular said gripping elements62, can be replaced in order to set up machine2with those gripping elements62that are most suitable for the protruding portion of lids “L”, by selecting the most appropriate connection portion623.

Said centring element3can position machine2above container “C”, while centring machine2itself and retaining container “C”, thus preventing container “C” from moving, without generating any compression forces on container “C”.

Said centring element3is able to position itself on container “C”, allowing gripping device6to engage with lid “L” without acting upon the outer top wall of container “C”, and also to retain lid “L”.

Said moving devices (5,64) allow lid “L” to be separated from container “C” and retained, through the use of said gripping elements62, still without acting upon the outer top wall of container “C”.

Said gripping elements62act exclusively upon lid “L”, without exerting any forces upon and/or abutting against container “C”.

Machine2according to the present invention avoids applying any forces onto container “C”, for the purpose of not causing any damage to container “C” following repeated removals of lid “L” between the different processing stages that the content of the same container “C” must undergo.

In one possible embodiment, machine2is positioned on container “C” manually, or in a servoassisted manner, by an operator. It is a task of the operator to appropriately centre machine2above container “C”. Once positioned, machine2is activated by the operator, e.g. through a two-hand control panel, in order to obtain the separation of lid “L” from container “C” and then open the latter.

In a more automated embodiment, the machine can, in a totally automatic manner, position and centre itself on container “C”, separate lid “L” from container “C”, and hold lid “L” to definitively remove lid “L” from container “C”.

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