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(11) | EP 1 172 157 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A process and an apparatus for the production of pile-up lids, and lids obtained thereby |
| (57) A process and an apparatus allow the easy production of cardboard pile-up lids (1),
the process provides the steps of positioning a lid (1) to be formed onto a supporting
structure (7); narrowing to an upper wall of the lid (1) a second structure (10) comprising
positioning means (12); narrowing forming means (13, 14) to the peripheral wall (3)
of the lid (1); forming said lid (1) by peripheral rolling said forming means (13,
14) on a side wall (3) of the lid (1); and moving away the forming means (13, 14)
from the peripheral wall (3). |
[0001] The present invention relates to a process for the production of pile-up lids and to an apparatus carrying out such process.
[0002] To date, a process for the production of pile-up lids and an apparatus carrying out such process are known. Once pressure-formed at the end of the process of the state of the art, such pile-up lids should have their top portion of a smaller diameter with respect to that of the bottom portion thereof, so as to ensure the piling up of one on top of another. Moreover, typically this type of lids has a peripheral bead performed onto the side surface thereof, that allows the snap-on engagement of the lid when the latter is arranged onto the peripheral edge of the container to be closed. Such process and apparatus are disclosed in the published European Patent Application N° 0 823 298 A2 of the same applicant. According to the state of the art, a process is disclosed providing the steps of positioning an unfinished lid on a supporting element, the former being then pressure-formed by narrowing in the radial direction a plurality of sectors until these come into contact with the walls of the lid inserted therebetween.
[0003] The process of such prior art, though applicable to lids of circular shape or the like, has the disadvantage of providing several forming steps.
[0004] Moreover, another disadvantage lies in the fact that to carry out such process an extremely complicated apparatus, both as to the configuration and the management thereof, is provided.
[0005] Further, such apparatus was found not to be faultlessly performing its function for the forming of substantially square-shaped lids with chamfered corners.
[0006] Hence, an object of the present invention is to overcome the above-mentioned disadvantages providing a process for the production of both circular and substantially square-shaped pile-up lids.
[0007] Another object of the present invention is to provide a process for the production of pile-up lids providing a limited number of intermediate forming steps, and above all of high forming speed, thereby improving productivity.
[0008] A further object of the present invention is to provide an apparatus for the production of pile-up lids that be both of simple implementation and extremely effective.
[0009] Hence, the present invention provides a process for the production of pile-up lids made of an upper wall and a peripheral wall, the process being characterised in that it comprises the following steps:
- positioning an unfinished lid onto a supporting element;
- narrowing a second structure comprising positioning means, until it contacts said upper wall (2) of said lid;
- narrowing near first and second forming means, until they contact the peripheral wall of said lid;
- forming said lid by peripheral rolling of said first and second means onto the peripheral wall of said lid; and
- moving away from the peripheral wall of the formed lid said first and second forming means.
[0010] Moreover, the present invention provides an apparatus for the production of pile-up lids made of an upper wall and of a peripheral wall, the apparatus being characterised in that it comprises:
- a first lid supporting structure;
- a second structure, movable with respect to said first lid supporting structure;
- first lid forming means;
- second lid forming means; and
- means for driving said second structure.
[0011] A detailed description of a preferred embodiment of the process and of the apparatus of the present invention will "be provided in the following, given as a nonlimiting example and with reference to the enclosed drawings, in which:
figure 1 shows a pile-up lid obtained with the process of the present invention;
figure 2 is an elevational and partially sectional front view of the lid shown in figure 1;
figure 3 is a first schematic front view partially showing the apparatus of the present invention;
figure 4 is a second partially sectional front view showing the apparatus of the present invention; and
figure 5 is a partially sectional front view of a detail of the apparatus of the present invention.
[0012] With reference to figures 1 and 2, they show a preferred embodiment of a pile-up lid formed with the process and the apparatus of the present invention.
[0013] According to the present invention, a pile-up lid 1 has an upper wall 2, a peripheral wall 3 being connected thereto. The peripheral wall 3 defines an upper lip 4 and a lower skirt 5 with respect to the upper wall 2. Once formed with the process of the present invention, the lip 4 has a smaller diameter with respect to the skirt 5. Moreover, onto the skirt 5 of the peripheral wall 3 a bead 6 is formed.
[0014] The lid 1 thus formed is characterised in that it can be piled up onto another lid identical thereto, and moreover it can be snap-engaged onto a respective complementary peripheral rim of a container by means of the bead 6.
[0015] With reference now to figure 3, it schematically shows the operation of the apparatus according to the process of the present invention.
[0016] According to the invention, the apparatus comprises a fixed supporting structure 7, substantially consisting of a first fixed base 8 piece-formed to a fixed frame (not shown in the figures). A second base 9 is mounted onto the first base 8, to support the unfinished lid 1. It has to be understood that the second base 9 is shaped so as to be complementary to the lid 1.
[0017] On the other hand, a second structure 10 (not in the figure and better illustrated hereinafter) movable along the vertical direction Y-Y is provided. The second movable structure 10 comprises a shaft 11, which is resilient along the vertical direction and having at the bottom end thereof, a first knurling gear 12. During the downstroke of the shaft 11 the knurling gear 12 is apt to engage with the upper wall 2 of the lid 1.
[0018] Onto the outer peripheral portion of the lid 1 the forming means are provided. As first forming means a second knurling gear 13, which is movable in the horizontal direction with respect to the lid as well as revolving the vertical axis thereof, is provided. When the knurling gear 13 contacts the upper lip 4 of the lid 1, the former has a diameter suitable to carry out a deformation of the lip 4 by pressing the material of the lid 1 until yield, by squashing the lip 4 between the knurling gear 12 and the knurling gear 13. Therefore, the complete forming of the lip 4 is carried out by rolling the knurling gear 13 along the entire perimeter of the upper lip 4, performing a plastic deformation, e.g. of the «reeded» type, apt to reduce the initial diameter of the lip 4. It has to be pointed out that, according to the process of the present invention and depending on the material of the lid 1, it is also possible to plastically deform the lip 4, so as to reduce its diameter, with respect to its initial one and the resulting surface not being necessarily knurled.
[0019] In fact, hereinafter for «knurling» merely a plastic deformation, given to the paper surface by exerting a relatively elevated and localised pressure thereon, is to be understood.
[0020] As second forming means a third knurling gear 14 is provided. The knurling gear 14 is both movable in the horizontal direction with respect to the lid 1 and revolving about its own vertical axis. The knurling gear 14 has a smooth outer surface, an outward-protruding peripheral rib 15 being formed thereon. In this case as well, in order to form the skirt 5 of the lid 1, firstly the knurling gear 14 is brought into contact with the skirt 5 of the lid 1, thus causing a localised deformation at the contact area onto the skirt 5 of the lid 1. Therefore, the complete forming of the skirt 5 is carried out by rolling the knurling gear 14 along the entire perimeter of the skirt 5. It has to be specified that the base 9 has a peripheral groove 90 complementary to the rib 15 of the knurling gear 14 to form the lid 1.
[0021] With reference now to figure 4, the apparatus 10 of the present invention will be illustrated in greater detail.
[0022] More precisely, for the vertical displacement of the shaft 11, as displacement means a cam 100 and rack 101 system is provided. The shaft is apt to slide within a guide 102. For the contacting of the knurling gear 12 with the upper wall 2 of the lid 1, the shaft 11 is resilient by means of a spring 103 (better illustrated hereinafter).
[0023] For displacing the knurling gears 13 and 14, the same revolvingly mounted on a supporting frame 16 coaxial to the shaft 11. Also the supporting frame 16 revolves around the base 7 and with respect to the shaft 11, as well as in the radial direction thereof in order to allow the displacement of the knurling gears 13 and 14 therein. For the displacement in the radial direction of the frame 16, a second frame 17 coaxially mounted onto the shaft 11 and also revolving about the latter, is provided (all better illustrated hereinafter).
[0024] For the synchronous revolution of the two frames 16 and 17, a pulley 18 mounted coaxially to the shaft 11 and located between the two frames 16 and 17 is provided, said pulley 18 being connected to a motor (not in figure) by means of a belt 19.
[0025] Furthermore, the frame 17 is apt to engage to a cam 20, coaxially and integrally arranged onto the shaft 11 so as to allow the knurling gears 13 and 14 to follow the outline of the lip of the underlying lid 1 along the entire forming revolution thereof (better illustrated hereinafter).
[0026] With reference now to figure 5, the apparatus and the operation thereof according to the present invention will be illustrated in further detail.
[0027] The first frame 16 has a supporting structure 160 for the knurling gear 13 which (160) is apt to slide in the radial direction on guides 161 against the resistance of one or more springs (not in figure). Likewise, the knurling gear 14 is mounted on a supporting structure 162 apt to slide on guides 163 against the resistance of one or more springs (not in figure). The first frame thus assembled is revolvingly mounted onto the resilient portion of the shaft 11 with a revolving support 164.
[0028] The frame 17 is coaxially mounted onto the non-resilient portion of the shaft 11 by means of a supporting element 170. The frame 17 has a first and a second structure 171 and 172, respectively resilient in the radial direction against the resistance of a spring 173. The first and the second structure 171 and 172 have at the top thereof two revolving supports 174 apt to mutually engage by rolling within a track 21 formed into the cam 20.
[0029] It has to be specified that the shape of the track 21 is complementary to that of the lid to be formed.
[0030] On the other hand, at the bottom portion of each structure 171 and 172, a protruding portion having a cam follower 175 apt to engage by rolling within a respective cam track 176 formed on each supporting structure 160 and 162, respectively, is integrally formed.
[0031] Furthermore, the pulley 18 is connected to the frame 17, in order to drive the rotary motion thereto.
[0032] For the operation, first the lid to be formed is positioned onto the base 9. Then the shaft 11 is lowered until the knurling gear 12 contacts the surface of the upper wall 2 of the lid 1.
[0033] Then, the shaft is further lowered against the resistance of the spring 103. The further lowering of the shaft 11 causes the contact of the cam followers 175 with the respective tracks 176, thus inducing a narrowing in the radial direction of the knurling gears 13 and 14, until the latter contacts the outer surface of the peripheral wall 3 of the lid 1. A further controlled lowering of the shaft 11 induces a reciprocal narrowing of the knurling gears 13 and 14 which is transformed into yield pressure or stress onto the surface of the lid, thus deforming the latter.
[0034] In this condition, the bottom protruding ends of the frame 17 engage the respective top ends of the frame 16.
[0035] Then the belt 19 is operated, which drags the pulley 18, thus also revolving the frame 17 and the underlying frame 16. The revolution of the frame 17 occurs following the outline of the cam track 21 that engages the supporting members 174 of the respective structures 171 and 172, thus also driving the motion to the underlying knurling gears 13 and 14 according to the outline of the track 21. During the revolution, the knurling gears 13 and 14 progressively deform the lip and the skirt 4 and 5, respectively, of the lid 1.
[0036] When the pulley 18 has performed a complete revolution, i.e. of 360°, the shaft can finally be lifted, progressively moving the knurling gears 13 and 14 away from the lid by means of the action of the springs located in the structures 160 and 162.
[0037] Then, the lid thus formed can be removed from the base 9 in order to position a new lid 1 to be formed onto the base 9 and to start the apparatus 10 for a new forming cycle.
[0038] It has to be specified that the process and the apparatus of the present invention are not limited to pile-up lids made in materials like cardboard or the like, also applying to lids in different materials having mechanical specifications analogous to those of cardboard.
[0039] Further, in a different embodiment of the apparatus of the present invention, it is possible to provide the forming of the lid 1 by revolving the same onto the base 9, and bringing it into contact with the knurling gears 13 and 14 in a locked position, rather than revolving the knurling gears 13 and 14 onto the outer peripheral wall 3 of the lid 1.
1. A process for the production of pile-up lids (1) made of an upper wall (2) and of
a peripheral wall (3), the process being characterised in that it comprises the following steps:
- positioning the lid (1) to be formed on a supporting structure (7);
- narrowing a second structure (10) comprising positioning means (12), until it contacts said upper wall (2) of said lid (1) ;
- narrowing first (13) and second (14) forming means until they contact the peripheral wall (3) of said lid (1);
- forming said lid (1) by peripheral rolling of said first (13) and second (14) means onto the peripheral wall (3) of said lid (1); and
- moving away from the peripheral wall (3) of said lid (1) thus formed said first (13) and second (14) forming means.
2. An apparatus (10) for the production of pile-up lids made of an upper wall (2) and
of a peripheral wall (3), the apparatus being characterised in that it comprises:
- a first supporting structure (7) for the lid (1);
- a second structure (10) movable with respect to said first supporting structure (7) for the lid (1);
- first forming means (13) for the lid (1);
- second forming means (14) for the lid (1);
- first means (100,101) for driving said second structure (10); and
- second means (18,19) for driving said first forming means (13) to said second forming means (14).
3. The apparatus (10) according to the preceding claim, wherein said first supporting
structure comprises a first fixed base (8), and a second base (9) for supporting the
lid (1) to be formed, said second base (9) being integrally formed with said first
base (8).
4. The apparatus (10) according to the preceding claim, wherein the shape of said second
base (9) is complementary to that of said lid (1) to be formed.
5. The apparatus (10) according to any of the claims 2-4, wherein said second structure
(10) comprises a shaft (11) movable in a direction perpendicular to said first supporting
structure (7), a cam (100) and a rack (101) device for the displacement of said shaft
(11).
6. The apparatus (10) according to the preceding claim, wherein said shaft (11) comprises
a contacting member (12) mounted at the bottom end thereof, the contacting member
(12) being apt to engage with upper wall (2) of said lid (1) and having a shape which
is complementary to that of said upper wall (2) of said lid (1).
7. The apparatus (10) according to any of the claims 2-6, further comprising:
- a first frame (16) coaxially and revolvingly mounted on said shaft (11) and movable in the radial direction with respect to the latter;
- a second frame (17) coaxially and revolvingly mounted on said shaft (11) and connected to said second driving means (18,19); and
- a cam member (20) integrally arranged onto said shaft (11) at the upper portion of said second frame (17) and apt to cooperate with said second frame (17), the arrangement being such that said first frame (16) is apt to cooperate with said second frame (17) so as to perform a displacement in the radial direction following to a reciprocal displacement of the second frame (17) in the vertical direction.
8. The apparatus (10) according to the preceding claim, wherein said first frame (16)
is apt to revolve about said shaft (11) after the engagement with said second frame
(17).
9. The apparatus (10) according to claim 7 or 8, wherein said cam member (20) has a track
(21) having a shape that is complementary to that of the lid (1) to be formed.
10. The apparatus (10) according to any of the claims 2-9, wherein said first forming
means comprises a first forming member (13) revolvingly mounted on said frame (16)
and apt to cooperate with said contacting member (12) during the forming of said lid
(1).
11. The apparatus (10) according to any of the claims 2-10, wherein said second forming
means comprises a second forming member (14) revolvingly mounted on said frame (16)
and apt to cooperate with said second supporting member (9) during the forming of
said lid (1).
12. The pile-up lid (1) obtained with the process and the apparatus of the preceding claims.