EP2528826B1

EP2528826B1 - A lift group for a wrapping machine

Info

Publication number: EP2528826B1
Application number: EP11711136.9A
Authority: EP
Inventors: Luca Baraldi; Flavio Giovannini
Original assignee: Cmfima SRL
Current assignee: Cmfima SRL
Priority date: 2010-01-29
Filing date: 2011-01-27
Publication date: 2013-11-13
Anticipated expiration: 2031-01-27
Also published as: WO2011092583A3; WO2011092583A2; EP2528826A2; ITRE20100005A1; IT1399241B1

Description

TECHNICAL FIELD

The present invention relates to wrapping lines for flat objects, substantially parallelepiped, such as for example bars of chocolate, which are to be sealedly enveloped in a first internal sheet of high-protection material, such as for example aluminium, and then in a second external sheet made of paper which is generally decorated in order to exhibit the mark and/or the characteristics of the product.

BACKGROUND ART

Known wrapping lines substantially exhibit a first part comprising a conveyor on which the articles advance, means for placing the articles at equal distances on the conveyor, means for enveloping the articles in the first sheet of high-protection material for food use, and means for welding and trimming the three open sides of the wrapping.
In line and downstream of the first part of the known wrapping machines there is a second machine part which comprises means for receiving wrappings which arrive from the first part of the machine, folding the flaps of the first sheet such as to make them adhere to the wrapping, and sending the wrappings with the flaps folded to a third machine part, where they are wrapped in the external second sheet, generally made of paper.
In known machines, the second part of the machine is constituted by a lift group which comprises a first lower platform associated to lift means, on which the article exiting from the first machine part is positioned.
The first platform raises the article from the conveyor of the first machine part up to the level of a conveyor belonging to the third machine part.
Normally these conveyors are singly constituted by conveyor belts.
During the raising the article is maintained on the first platform by a second upper platform which lowers onto the article located on the first platform and maintains it pressed during the raising.
During the raising trajectory a sheet metal apron is positioned, having the same plan dimensions of the article, and which has the function of folding downwards the welded flaps of the wrapping created from the first sheet, in adherence to the vertical flanks of the article.
Folding means are positioned above the sheet metal apron which are destined to cause the flaps, already folded downwards, to adhere to the lower surface of the article, while at the same time supporting the article itself.
Finally, the article resting on the folding means is dragged laterally and raised onto the conveyor belts of the third machine part.
In the meantime, the first platform can lower in order to receive a further article and, after the first article has been transferred onto the third machine part, the second platform can in turn descend.
A machine of this type is completely described in UK patent no. GB1056830 . The functioning of the lift group of known machines is excessively wasteful in terms of time, and causes a slowing-down in the productivity of the whole machine.
An aim of the present invention is to remedy this drawback by providing a lift group for a wrapping machine in which the raising of the article and the folding of the flaps of the first sheet covering the article are coordinated such as to be faster overall.

DISCLOSURE OF INVENTION

The aim is attained by a lift group having the characteristics set out in the independent claim.
The dependent claims illustrate improvements to the invention, aimed at increasing its efficiency.
The lift group of the invention is located at the end of a conveyor line, typically made up of two parallel belts, on which articles advance, which articles comprise an internal bar, substantially parallelepiped, covered by a first sheet of material folded on the article and having three welded flaps projecting laterally and posteriorly of the article.
In proximity of the terminal end of the belts, the lift group comprises a rest element destined to be initially in a lowered position and in a first operative configuration, in which it is vertically aligned below a collecting position of the article.
The rest element is preferably comprised, in plan view, in the space comprised between the belts of the conveyor line.
First movement means are associated to the rest element such as to move the rest element vertically between the lowered position and a raised position, in which the rest element, in the first operative configuration, is coplanar with a sliding plane, which is preferably at a same level as the upper conveyor of the terminal part of the wrapping line.
In this way, the rest element raises the article which is in the collecting position of the lower conveyor line and takes it to the level of the upper conveyor.
Along the raising trajectory there is a folding apron, which the article resting on the rest element passes through, and which drags on three sides of the article in order to fold the three flaps of the wrapping, setting them adjacent to the vertical sides of the article.
The folding apron is preferably a sheet metal tube, substantially rectangular, having a vertical axis and open on a side like a channel, having walls that converge in an upwards direction and having, in the narrowest section thereof, the same shape and dimensions as the article seen in plan view. Folding means are located above the apron, preferably in the form of plates, which are located substantially coplanar to the upper sliding plane and are destined to fold the three flaps of the wrapper further against the lower surface of the article.
The folding means in the form of plates are also destined to support the article before its transfer onto the upper conveyor belts, which is achieved using extractor means destined to drag the article onto the sliding plane, removing it from the folding means.
In the invention, the lift group further comprises second movement means destined to displace the rest element between the first operative configuration, mentioned herein above, and a second operative configuration, in which the rest element is external of the plan shape of an article in the collecting position.
The second movement means are preferably configured such as to impress a rotary movement on the rest element about a horizontal axis, inclining it downwards such that it will remain comprised in the space between the belts of the lower conveyor.
Thanks to this solution, it is advantageously possible to obtain a shorter cycle time with respect to the prior art, which enables a significant increase in the production capacity of the whole wrapping line.
In the prior art, after raising each article the lower platform has to newly descend to the initial position before the lower conveyor belts can advance and bring another article into the collecting position.
With the lift group of the invention, however, the belts of the upstream conveyor can locate the new article in the collecting position when the rest element is still raised, as the subsequent descent towards the initial position will be performed with the rest element in the second operative configuration, i.e. in which it is inclined and it does not interfere with the new article in the collecting position.
In a preferred aspect of the invention, the lift group further comprises means for coordinating the first and second movement means, such as to displace the rest element from the second to the first operative condition during the descent from the raised position to the lowered position, impressing on it a roto-translating motion thanks to which the rest element, during the descent, does not interfere with the new article in the collecting position.
The coordinating means preferably comprise an electronic card programmed to control the first and the second movement means, but might alternatively comprise kinematic organs destined to connect the first and the second movement means, such as to form a single kinematic chain destined to guarantee synchronisation of the various displacements.
In a further aspect of the invention, the lift group further comprises a blocking element destined to be superposed on the rest element when the rest element is in the first operative condition, such as to block the article thereon during the displacement from the lowered position to the raised position. The blocking element can be completely deconstrained from the rest element.
In this case the lift group comprises third movement means for vertically displacing the blocking element, and electronic or kinematic means for coordinating the third movement means with the first movement means of the rest element, such that the blocking element displaces solidly with the rest element from the lowered position to the raised position.
Alternatively, the blocking element and the rest element can be borne by a same vertically-mobile carriage, preferably hinged thereto, such as to realise a sort of pliers, of which the blocking element and the rest element constitute the jaws.
The advantages and the constructional and functional characteristics of the invention will emerge from the detailed description that follows, which with the aid of the accompanying figures of the drawings illustrate a preferred but not exclusive embodiment, given by way of non-limiting example.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic illustration of a central portion of a wrapping line, which is provided with a lift group according to a first embodiment of the invention;
figure 2 and figure 3 are respectively plan and elevated views of the wrapper which is to be processed by the lift group of figure 1;
figure 4 is a detail of the lift group of figure 1 in an operative position, in a lateral view;
figure 5 is the lift group of figure 4 in a different operative position, seen in a side view;
figure 6 is the lift group of figure 5 in a different operative position, seen in a side view;
figure 7 is a view from above of figure 6, in a different operative position;
figure 8 is the view from VIII of figure 7, in a different operative position;
figure 9 is a schematic illustration of a central portion of a wrapping line, which is provided with lift group in a different embodiment, seen in a side view;
figures 10 and 11 show the lift group of figure 9 in two different operative positions.

BEST MODE FOR CARRYING OUT THE INVENTION

The figures illustrate a wrapping line 1 comprising a first conveyor 3, a central part 2 according to the invention, and a second conveyor 10 located at a higher level than the first conveyor 3.
In particular, the first conveyor 3 comprises two parallel conveyor belts 33, visible in figure 8, on which the articles 4 to be processed advance in equidistanced order.
As illustrated in figures 2 and 3, the articles 4 comprise a bar 41, substantially parallelepiped, covered by a wrapper 42 of a first wrapping sheet folded on a side 410 and welded on the other sides to form three projecting flaps 411, 412 and 413.
The conveyor belts 33 step-advance to successively bring the articles 4 into a collecting position A, located in proximity of the end thereof, where raising means belonging to the central part 2 can operate on them.
As illustrated in figure 4, the raising means comprise a carriage 5 which runs on a vertical rail 6 and is connected by a con rod 7 to a crank 8, the shaft 9 of which is connected to an controlled-displacement electric motor, not illustrated.
The carriage 5 comprises a rest element 52, which is hinged to a horizontal-axis shaft 51 and is borne by the carriage 5, from which a lever 53 originates which is connected by a con rod 54 to a crank 55 of a shaft 56 connected to an controlled-displacement electric motor (not illustrated).
With particular reference to figure 8, the rest element 52 has a transversal dimension which is smaller than a distance between the belts 33 and can pass between them to be located below them. In particular it comprises two arms 520 which each support a base 521. The rest element 52 can oscillate on board the carriage 5, in both directions, between a first operative configuration illustrated in figure 5, in which the bases 521 are horizontal, facing upwards and vertically aligned with the article 4 in a collecting position A, and a second operative configuration illustrated in figure 4, in which the bases 521 are inclined downwards, such as to exit from the plan outline of the article 4 which is in the collecting position A.
Further, the rest element 52 can displace vertically together with the carriage 5, between a lowered position illustrated in figure 5 and a raised position illustrated in figure 6.
A blocking element 511 is also hinged to the shaft 51, which blocking element 511 has substantially a plate-shape and, together with the rest element 52, defines overall a pliers device 50 of which the rest element 52 constitutes the lower jaw and the blocking element 511 constitutes the upper jaw.
The blocking element 511 is destined to be in an active configuration, illustrated in figures 5 and 6, in which it is parallel to and superposes the rest element 52, when the rest element 52 is in turn in the horizontal configuration, such as to press and block the article 4 thereon.
The blocking element 511 can further oscillate on-board the carriage 5 in both directions, between the active configuration and an inactive configuration, illustrated in figure 4, in which it is upwardly-inclined in order to free the article 4.
The rotations of the blocking element 511 are independent from those of the rest element 52,and in particular they are transmitted by a gear 512 rotating on a shaft 510 borne by the carriage 5 and coupled with a gear 513 solidly constrained to the blocking element 511.
The gear 512 comprises a lever 514 connected by a con rod 540 to a crank 550 of a shaft 560 connected to an controlled-displacement electric motor (not illustrated).
A folding apron 11 is located above the collecting position A, exactly in axis with the rest element 52 when in the horizontal configuration, which folding apron 11 remains stationary and has three sides that are adjacent to the three rear and lateral sides of the article 4, such as to fold the projecting flaps 411, 412, 413 downwards when the article 4 passes internally of the apron 11, raised by the rest element 52.
With particular reference to figures 7 and 8, the apron 11 has a vertical-axis rectangular tube configuration, open on a side 110, like a channel, with the walls 11 converging in an upwards direction, and having the same shape as the article 4 seen in plan view.
The apron 11 enables passage of the blocking element 511, while the shaped arms 520 of the rest element 52 rest below the apron 11.
As illustrated in figures from 4 to 6, a sliding plane 12 (not visible in figure 7) is located above and by the side of the apron 11, which sliding plane 12 is located substantially coplanar both to the second conveyor 10 and to the bases 521 of the rest element 52, when the rest element 52 is in the raised position and in the horizontal configuration.
The sliding plane 12 is further coplanar with the rear and lateral folding means in the form of plates, respective 13, 14 and 15 (see figure 7).
The folding plates 13, 14, 15 are destined to near one another, being placed below the article 4 supported by the rest element 52 in a raised position such as to fold the flaps 411, 412 and 413 flush to the lower surface of the article 4.
The plate 13 has a profiled form which is complementary to the shape of the rest element 52 such as to be crossable thereby.
Apart from folding the flaps, the folding plates 13, 14 and 15 support the article 4 and enable the rest element 52 to descend towards the lowered position.
An extractor device 16 is located in front of the rear plate 13 and is substantially coplanar thereto; it is destined to drag the article 4, supported by the folding means, onto the sliding plane 12 and from there onto the second conveyor 10.
The movement of the rear plate 13 and the extractor 16 is the task of the con rod-crank systems, similar to those which activate the rest element 52 and the blocking element 511, visible in figure 1.
As illustrated in figure 8, the movement of the plates 14 and 15 is done by respective support shafts 140 and 150, which are activated in opposing phase by a lever 17 which is hinged at an intermediate point 170, effectively like a rocker arm.
The invention functions as follows.
The start-cycle configuration is illustrated in figure 4, in which the article 4 is already in the collecting position A at the end of the belts 33 of the first conveyor 3.
The rest element 52 is in an inclined configuration and is descending without interfering with the article 4 which is in the collecting position A.
During the last part of the descending run, the rest element 52 starts to displace from the inclined configuration towards the horizontal configuration, thus overall performing a roto-translating motion, such that at the end of the descent run the rest element 52 is contemporaneously in the lowered position and in a horizontal configuration, as shown in figure 5.
This roto-transiating motion is obtained by means of an electronic card (not illustrated) which is destined to coordinate and synchronise the motors which respectively activate the activating cranks 8 and 55.
At the end of this stage, the article 4 is rested on the bases 521 of the rest element 52 and is maintained in position by the blocking element 511 which in turn is in the active configuration.
The pliers denoted by 50 are closed and grip the article 4 in a vice-like hold. At this point, while maintaining the rest element 52 in the horizontal configuration and the blocking element 511 in the active configuration (with the pliers 50 closed), the carriage 5 rises up to come into the position illustrated in figure 6, in which the article 4 is located exactly just above the level of the plates 13, 14 and 15 after having passed through the apron 11. The plates 13, 14 and 15 are then advanced up to being arranged below the article 4, after which the pliers 50 are opened, i.e. the blocking element 511 is rotated into the inactive configuration in order to enable the extractor 16 to drag the article 4 onto the sliding plane 12 and then onto the second conveyor 10, while the rest element 52 is rotated into the inclined configuration, in order to enable it to descend thereafter without interfering with a new article 4 which, in the meantime, has been brought into the collecting position A from the first conveyor 3.
While the pliers 50 descend, the plates 13, 14 and 15 of the folders can return to the starting position, creating the space for the passage of the next article 4.
During the descent run of the pliers 50, the blocking element 511 is returned into the active configuration and at the same time the rest element 52 is returned into the horizontal configuration, as described herein above.
In this way, the pliers 50 newly close to collect the next article 4, and the cycle is repeated.
In figures from 9 to 11, an alternative embodiment of the wrapping line 1 is described, which differs from the preceding embodiment only as far as the aspects described in the following are concerned.
In this case, the blocking element 511 is completely deconstrained from the carriage 5 which bears the rest element 52, and is associated to respective activating means destined to move it in a vertical direction.
In the illustrated example, the activating means comprise a vertical-axis stem 515, to the lower end of which the blocking element 511 is fixed.
The stem 515 is slidably inserted in a guide bushing 516 and is connected via a con rod 517 to a crank 518 of a shaft 519 connected to an controlled-displacement electric motor (not illustrated).
This motor is controlled by an electronic card (not illustrated), which is programmed to control, in a coordinated way, also the functioning of the motor of the crank 8 which causes the carriage 5 to rise and fall, such that the invention functions as follows.
The start-cycle configuration is the one illustrated in figure 9, in which the rest element 52 is in the lowered position and in the horizontal configuration below the article 4 which is in the collecting position A on the belts 33.
The blocking element 511 is brought by the stem 515 to a height which is such as to block the article 4, pressing it against the rest element 52.
At this point, the rest element 52 is raised towards the raised position, and at the same time the blocking element 511 is also raised such that the reciprocal distance there-between remains constant.
This configuration is maintained during the whole upwards run, up to bringing the article 4 into the position illustrated in figure 10, in which the article 4 is located exactly just above the height of the folding plates 13, 14 and 15, after having crossed the apron 11.
The plates13, 14 and 15 are then advanced up to being arranged below the article 4, after which the blocking element 511 is further raised, in order to enable the extractor 16 to drag the article 4 onto the sliding plane 12 and then onto the second conveyor 10, while the rest element 52 is rotated towards the inclined configuration in order to enable it thereafter to descend without interfering with a new article 4 which, in the meantime, has been brought into the collecting position A by the first conveyor 3.
When the article 4 has been placed on the second conveyor 10, the folding plates 13, 14 and 15 can return to the start position, thus creating the space for the passage of the blocking element 511, which is lowered such as to return into the initial position in contact with the new article 4 (see figure 11). At this point, the rest element 52 is lowered in the same way as described for the first embodiment, i.e. by a roto-translating motion, such that at the end of the run the rest element 52 is contemporaneously in the lowered position and in the horizontal configuration.
The invention is not limited to the actuating mode described herein above, and modifications and improvements can be made to the actuation of the invention without its forsaking the ambit of protection of the following claims. In particular, two identical groups can be provided in series, in the case in which the bar has a first wrapper welded on three sides, and a further external wrapping folded on the first wrapping.
In this case, a known device for supplying the external wrapping can be located between the first and the second of the two groups.

Claims

A lift group for a wrapping machine, destined to collect an article (4) from a collecting position (A) of a first conveyor (3), which article (4) is conformed as a bar (41) superiorly wrapped by a sheet (42) having at least three projecting flaps (411, 412 and 413) from three sides of the bar (41), and to place the article (4) on a second conveyor (10) located at a higher level after folding the at least three flaps (411, 412, 413) adjacently to the bar (41), the lift group comprising:
a rest element (52) destined to be in a lowered position and in a first operative configuration in which it is vertically-aligned below the collecting position (A) of the article (4);

first movement means for vertically displacing the rest element (52) between the lowered position and a raised position, in which the rest element (52), in the first operative configuration, is coplanar to a sliding plane (12);

a folding apron (11) located on a vertical trajectory of the rest element (52),

such as to position the projecting flaps of the sheet (42) adjacent to the vertical sides of the article (4);

folding means (13, 14, 15) that are coplanar to the sliding plane (12) such as to fold the three flaps (411, 412, 413) further against the lower side of the article (4), and contemporaneously to support the article (4); and

extractor means (16) for dragging the article (4) onto the sliding plane (12),

removing it from the folding means (13, 14, 15);

the lift group being characterised in that it comprises:
second movement means for displacing the rest element (52) between the first operative configuration and a second operative configuration, in which it is external of a plan profile of the article (4) in the collecting position (A).
The group of claim 1, characterised in that the second movement means are configured such as to impress a rotary movement on the rest element (52) about a horizontal axis.
The group of claim 1, characterised in that it comprises coordinating means of the first and second movement means, such as to impress on the rest element (52) a roto-translating motion which contemporaneously displaces the rest element (52) from the raised position to the lowered position and from the second operative configuration to the first operative configuration.
The group of claim 3, characterised in that the coordinating means comprise an electronic card programmed to control the first and the second movement means.
The group of claim 1, characterised in that the first conveyor comprises two belts (33), and in that the rest element (52) is contained internally of a space defined by the belts (33).
The group of claim 1, characterised in that it comprises a blocking element (511) destined to be superposed on the rest element (52), when the rest element (52) is in the first operative configuration, such as to block the article (4) thereon during displacement from the lowered position to the raised position.
The group of claim 6, characterised in that it comprises:
third movement means for vertically displacing the blocking element (511); and

coordinating means of the third movement means with the first movement means, such that the blocking element (511) displaces solidly with the rest element (52) from the lowered position to the raised position.
The group of claim 1, characterised in that the rest element (52) is supported by a carriage (5) sliding on a vertical guide (6), and in that the movement means comprise a con rod (7) destined to connect the carriage (5) to a crank (8) of a shaft (9) activated by a controlled-advancement motor.
The group of claim 8, characterised in that the carriage (5) bears a first shaft (51) to which the rest element (52) is hinged, and in that the second movement means comprise a lever (53) associated to the first shaft (51) and a con rod (54) destined to connect the lever (53) to the crank (55) of a shaft (56) activated by a controlled-advancement motor.
The group of claim 6 and 9, characterised in that the blocking element (511) is also hinged to the first shaft (51), which blocking element (511) is commanded to rotate by a gear (513) solidly constrained to the blocking element (511) and coaxial with the first shaft (51), which enmeshes in a second gear (512) located on a second shaft (510) parallel to the first shaft (51) and connected by a con rod (540) to a crank (550) of a shaft (560) activated by a controlled-advancement motor.
The group of claim 1, characterised in that the folding apron (11) comprises a vertical-axis sheet-metal tube, having an open side and having walls which converge in an upwards direction, and also having, in a narrowest section thereof, same dimensions as the article (4).
The group of claim 1, characterised in that the means for further folding the flaps (411, 412, 413) against the lower side of the article (4) are singly constituted by a plate (13, 14, 15) which is mobile between a completely external position to the article (4) and a second position partially underlying the article (4).
The group of claim 12, characterised in that the means for further folding the flaps (411, 412, 413) against the lower side of the article (4) comprise two coplanar lateral plates (14, 15) each supported by a respective shaft (140, 150) connected to a rocker arm (17) activated by a controlled-advancement motor such as to move in opposite directions and in symmetry with the other shaft.
The group of claim 12, characterised in that the means for further folding the flaps (411, 412, 413) against the lower side of the article (4) comprise a rear plate (13) having a shape which is complementary to a profile of the rest elements (52) and destined to be crossed thereby.
The group of claim 1, characterised in that the extractor means (16) are mobile from a position in which the said extractor means (16) are located behind the article (4) resting on the folding means (13, 14, 15), and a position in which the extractor means (16) are located beyond a start point of a coplanar conveyor located downstream, being connected by a con rod to a crank of a shaft activated by a controlled-advancement motor.