|
(11) | EP 1 829 628 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||
| (54) | Apparatus for making a metal lid, method for making said lid and metal lid thus made |
| (57) Apparatus (10) and method for making a metal lid (12) comprising a threaded tubular
portion (12a). The apparatus (10) comprises at least a cutting and molding station
(15), in correspondence with which, from a substantially plane metal sheet (11), a
disc (111) is obtained, which by means of progressive drawing is transformed into
a lid (12) in a single piece with the tubular portion (12a), and a threading station
(30) in which the tubular portion (12a) is provided with threading.
|
FIELD OF THE INVENTION
[0001] The present invention concerns an apparatus and a method for making a metal lid, advantageously able to be used for making pressurized tins for containing coffee beans.
BACKGROUND OF THE INVENTION
[0002] Pressurized metal tins used to contain coffee grains are known, comprising a cylindrical shaped shell, or central body, associated at the two ends respectively with a bottom and a lid provided centrally with an opening in turn closed by a removable cap.
[0003] The components of the tin, in order to guarantee the desired sealing, advantageously must be welded together.
[0004] In such cans, in order to guarantee the right conditions for preserving the coffee, a non-toxic gas is introduced, whose pressure adds to the pressure of the gasses which are released naturally by the coffee, so that the internal pressure of the tin might reach the value of 5-7 bar if there was not a regulating valve, or safety valve, on the cap, cooperating with a threading made on the lid.
[0005] In the state of the art, the threading is made in a sleeve associated with the lid by welding, with the disadvantage of high costs and the presence of a structural discontinuity in the lid.
[0006] Purpose of the present invention is to achieve an apparatus and a method which will allow to produce, starting from a substantially plane metal sheet, a metal lid, provided with a threading on which a safety valve, a closing cap or other can be screwed.
[0007] Another purpose of the invention is to make a metal lid of the type described above in a completely automatic manner and with limited costs.
[0008] The Applicant has devised and embodied the present invention to overcome the shortcomings of the state of the art in order to achieve the above purposes and to obtain other advantages.
SUMMARY OF THE INVENTION
[0009] The present invention is set forth and characterized essentially in the main claims, while the dependent claims describe other innovative characteristics of the invention.
[0010] In accordance with the above purposes, an apparatus for making a metal lid according to the present invention comprises at least a cutting and molding station able to cut and draw a substantially plane metal sheet so as to obtain a lid provided with a tubular portion, and a threading station able to thread said tubular portion.
[0011] Advantageously, there is at least a lubricating station upstream of the cutting and drawing station, able to cover at least one surface of the metal sheet with lubricant, before it is molded.
[0012] In a preferential form of embodiment, the cutting and molding station comprises at least a shearing unit for cutting a disc of sheet and a plurality of drawing units able to act in progression on said disc.
[0013] In a possible form of embodiment, the shearing unit and the drawing units are disposed in series.
[0014] According to a variant, the shearing unit and the drawing units are mounted on a turntable structure and are able to cooperate with specific workstations.
[0015] According to another variant, the cutting and molding station comprises a plurality of turntable structures, on each of which a shearing unit and a plurality of drawing units are mounted, so as to contemporarily form a plurality of lids.
[0016] According to a further variant, the cutting and molding station comprises at least a work unit where a shearing means, able to cut the metal sheet, is integrated with drawing means able to perform at least part of the shaping of the metal sheet.
[0017] In a preferential form of embodiment, the threading station comprises at least a roller device provided with two counter-rotating threaded rollers able to cooperate respectively with the internal surface and the external surface of the tubular portion of the lid, so as to perform the threading thereon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:
- fig. 1 is a schematic representation of the apparatus for making a metal lid according to the present invention;
- fig. 2 is a schematic front view of the transformation of a metal sheet into a metal lid by means of the method according to the present invention;
- fig. 3 is a schematic view from above of the transformation in fig. 2.
DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF EMBODIMENT
[0019] With reference to the attached drawings, the number 10 denotes generally the apparatus according to the present invention, by means of which it is possible to make, in a completely automatic manner, a metal lid 12, with a circular base, a central hole and a threaded tubular portion 12a, starting from a substantially plane metal sheet 11, advantageously of a rectangular shape.
[0020] The apparatus comprises, in the following order: a pick-up station 13, a lubricating station 14, a cutting and molding station 15, a threading station 16 and a discharge station 17.
[0021] The pick-up station 13 comprises an accumulation zone 18, in correspondence with which a plurality of rectangular metal sheets 11, of suitable size and a width comprised between 0.2 mm and 0.55 mm, advantageously about 0.4 mm, is stacked, and a manipulator with suckers 19, able to pick up one metal sheet 11 at a time and carry it to the lubricating station 14.
[0022] The lubricating station 14 comprises a hood 22 under which a distributing device 20 is present, provided with a plurality of nozzles 21, able to cover the sheets 11 with a layer of oil, or other lubricant.
[0023] A slider 23 is present under the distributing device 20, able to carry, one at a time, the lubricated sheets 11 to the cutting and molding station 15.
[0024] The cutting and molding station 15 comprises a shearing unit 34, able to shear the sheets 11 so as to achieve on each occasion a disc 111, and five drawing units 35a, 35b, 35c, 35d and 35e, disposed in series, able to determine a progressive deformation, through pressure and sliding of the material, of the disc 111. Suitable pressure means, or sheet-pressers, are present in order to control the sliding of the metal sheet.
[0025] In this case, the disc 111 exiting the shearing unit 34 has a diameter comprised between 230 mm and 260 mm, advantageously about 245 mm.
[0026] It comes within the field of the invention to provide that two operations are performed in one station, or in the work unit of a station, depending on the type of metal sheet and on its thickness.
[0027] There is a conveyor belt 24 at the exit of the cutting and molding station 15, by means of which the lids 12 are carried towards the threading station 16.
[0028] The threading station 16 comprises a manipulator with suckers 25 able to pick up the lids 12 one at a time and position them on a supporting surface 26 associated with a slide 27.
[0029] The threading station 16 also comprises a roller device 30 provided with two counter-rotating threaded rollers 28 and 29, by means of which the threading of the tubular portion 12a of the lid 12 is performed; a first roller 28 is able to be disposed inside the tubular portion 12a, while a second roller 29 is able to be disposed outside the tubular portion 12a.
[0032] The manipulator with suckers 19 picks up a metal sheet 11 from the accumulation zone 18 and takes it below the hood 22 where it is covered with a layer of oil by the distributing device 20.
[0033] The slider 23 then takes the metal sheet 11 to the cutting and molding station 15, where it is punched by the shearing unit 34 so as to obtain the disc 111 (figs. 2b and 3b).
[0034] The disc 111 is then taken into correspondence with a first drawing unit 35a, where it is drawn in order to make a circular impression 32 in the center, with a diameter comprised between 90 mm and 110 mm, advantageously about 100 mm.
[0035] The disc 111 is then taken to a second drawing unit 35b, where the depth of the circular impression 32 is accentuated and its diameter reduced, for example to about 80 mm (figs. 2d and 3d).
[0036] The disc 111 is then taken in correspondence with the third drawing unit 35c, whose punch tool causes a further increase in depth and a further reduction in diameter of the circular impression 32, as well as making a central hole 33, with a diameter of about 35 mm (figs. 2e and 3e); it is then taken to the fourth drawing unit 35d where the shaping of the circular impression 32 is completed, making a substantially cylindrical shape with a diameter of about 60 mm, and the hole 33 is widened until it reaches a diameter of about 45 mm (figs. 2f and 3f).
[0037] The presence of suitable pressure means in each drawing unit 35a-35d allows to control the movement of the metal sheet of which the disc 111 is made.
[0038] Finally, the first disc 111 is taken in correspondence with the fifth drawing unit 35e which gives the lid its final shape, with a further widening of the central hole 33 to about 50 mm in diameter, and forming a circumferential edge 12b about 15 mm in height (figs. 2g and 3g).
[0039] The lids thus obtained are discharged by the conveyor belt 24 and picked up, one at a time, by the manipulator with suckers 25 that deposits them on the supporting surface 26 of the threading station 16, so that they can be worked by the roller device 30.
[0040] The first roller 28 moves into the tubular portion 12a in contact with the internal surface thereof, while the second roller 29 is disposed in an opposite position to the first roller 28, in contact with the external surface of the tubular portion 12a.
[0041] The two rollers 28 and 29 are driven so as to perform, while rotating around their axis, a revolution around the tubular portion 12a, which determines the threading thereof.
[0042] The lid 12 thus completed, which in this case has a diameter comprised between 210 mm and 230 mm, advantageously about 220 mm, has a tubular portion 12a with an external diameter equal to about 60 mm and a central hole of about 50 mm in diameter, and is then discharged from the apparatus 10 by means of the slide 27 and the conveyor belt 31.
[0043] It is clear, however, that modifications and/or additions of parts may be made to the apparatus 10 and to the method for making a metal lid 12 as described heretofore, without departing from the field and scope of the present invention.
[0044] For example, different devices can be provided for moving the sheets 11 and the lids 12, instead of the manipulators with suckers 19 and 25, the slider 23 and the conveyor belts 24 and 31.
[0045] Also, the cutting and molding station 15 could comprise three turntable structures, each provided with a shearing unit 34 and with five drawing units 35a-35e, which are able to be disposed, one at a time, in correspondence with a workstation where they act upon the metal sheet 11 or a relative disc 111, so as to produce three lids 12 simultaneously.
1. Apparatus for making a metal lid, comprising a threaded tubular portion, characterized in that it comprises at least a cutting and molding station (15), in correspondence with
which, from a substantially plane metal sheet (11), a disc (111) is obtained, which
by means of progressive drawing is transformed into a lid (12) in a single piece with
said tubular portion (12a), and a threading station (30) in which said tubular portion
(12a) is provided with a threading.
2. Apparatus as in claim 1, characterized in that said cutting and molding station (15) comprises at least a shearing unit (34) for
obtaining said disc (111) from said metal sheet (11) and a plurality of drawing units
(35a, 35b, 35c, 35d, 35e), equipped with sheet-pressing means, able to progressively
shape said disc (111), causing said disc (111) to slide in a central zone (32) thereof
so as to obtain said tubular portion (12a).
3. Apparatus as in claim 1 or 2, characterized in that said cutting and molding station (15) comprises at least a work unit in which a shearing
means, in order to obtain said disc (111), is integrated with drawing means able to
perform at least part of the shaping of said disc (111).
4. Apparatus as in claim 2 or 3, characterized in that said shearing unit (34) and said drawing units (35a, 35b, 35c, 35d, 35e) are disposed
in series.
5. Apparatus as in claim 2 or 3, characterized in that said shearing unit (34) and said drawing units (35a, 35b, 35c, 35d, 35e) are mounted
on a turntable structure.
6. Apparatus as in claims 2 and 5, characterized in that said cutting and molding station (15) comprises a plurality of turntable structures
for the simultaneous shaping of a plurality of lids (12).
7. Apparatus as in any claim from 2 to 6, characterized in that said shearing unit (34), or said work unit, comprises shearing means, able to make
a plurality of discs (111) from said metal sheet (11), to undergo shaping.
8. Apparatus as in any claim hereinbefore, characterized in that said threading station (16) comprises at least a roller device (30) provided with
two threaded rollers (28, 29).
9. Apparatus as in any claim hereinbefore, characterized in that it further comprises first manipulator means (25) able to pick up, at least one at
a time, the lids (12) exiting from said cutting and molding station (15) and take
said lids (12) in correspondence with said threading station (16).
10. Apparatus as in any claim hereinbefore, characterized in that it further comprises, upstream of said cutting and molding station (15), at least
a lubricating station (14) able to cover at least a part of the surface of said metal
sheet (11) with a lubricant.
11. Apparatus as in claim 10, characterized in that said lubricating station (14) comprises at least a hood (22) under which there is
a distributing device (20) for said lubricant.
12. Apparatus as in claim 10 or 11, characterized in that it comprises second manipulator means (19) able to take said metal sheet (11) from
a pick-up station (13), in which a plurality of sheets (11) are stacked, to said lubricating
station (14).
13. Apparatus as in claim 9 or 12, characterized in that said manipulator means (19, 25) are of the sucker type.
14. Apparatus as in any claim from 10 to 13, characterized in that it further comprises slider means (23) able to take said metal sheet (11) from said
lubricating station (14) to said cutting and molding station (15).
15. Method for making a metal lid comprising a threaded tubular portion, characterized in that it comprises at least the following steps:
- cutting a substantially plane metal sheet (11) so as to obtain therefrom at least one disc (111) to be shaped;
- shaping said disc (111), by means of progressive drawing, in order to obtain said lid (12) in a single piece with said tubular portion (12a);
- making a threading on said tubular portion (12a).
16. Method as in claim 15, characterized in that said metal sheet (11) is cut by shearing.
17. Method as in claim 15 or 16, characterized in that the threading on said tubular portion (12a) is made by rolling.
18. Method as in any claim from 15 to 17, characterized in that said metal sheet (11) has a thickness comprised between 0.2 mm and 0.55 mm, advantageously
about 0.4 mm.
19. Method as in any claim from 15 to 18, characterized in that it comprises at least a step in which said metal sheet (11), or said disc (111),
is lubricated before said disc (111) is shaped.
20. Method as in any claim from 15 to 19, characterized in that said disc (111) has a diameter comprised between 230 mm and 260 mm, advantageously
245 mm.
21. Metal lid comprising a threaded tubular portion, characterized in that said threaded tubular portion (12a) is made in a single piece with the remaining
part of said lid (12).
22. Metal lid as in claim 21, characterized in that it is made with a shaped metal sheet (11) with a thickness comprised between 0.2
mm and 0.55 mm, advantageously about 0.4 mm.
23. Metal lid as in claim 21 or 22, characterized in that it has a diameter comprised between 210 mm and 230 mm, advantageously about 220 mm.
24. Metal lid as in claim 21 or 22, characterized in that said tubular portion (12a) has an external diameter of about 60 mm and a central
hole (33) of about 50 mm.