[0001] The invention relates to a method for manufacturing metal can bodies comprising the
steps of:
1) providing metal sheets of which the width is a little greater than the periphery
of a can body and the length corresponds to the height of a can body;
2) transporting successive sheets in lengthwise direction;
3) bending the sheet metal transversely of the lengthwise direction of the path such
that the edge zones mutually overlap;
4) mutually adhering the overlapping portions of the edge zones.
Also the invention relates to a device for performing the method as claimed in any
of the foregoing claims for manufacturing metal can bodies, which device comprises:
- conveyor means for feeding metal sheets and carrying away can bodies;
- bending means for bending the sheets of the conveying direction during feeding thereof
such that the edge zones are placed and held in overlap; and
- adhering means for mutually adhering the overlapping portions of the edge zones for
forming of successive can bodies;
Such a method and device are known from EP-A-0 205 992. It is a purpose of the
invention to provide a technique that allows a very ready applying of an internal
coating on the bodies obtained with the prior art method and apparatus.
In view thereof the method of the invention is characterized by 5) applying an internal
coating on these bodies using an applying device carried by an arm, which extends
in lengthwise direction from a region located upstream of the region were the edge
zones are made to overlap.
The device according to the invention is characterized by an applying device for applying
an internal coating on these bodies, which applying device is carried by an arm which
extends in lengthwise direction from a region located upstream relative to the adhering
means.
Full continuity can be ensured for instance with a method characterized by
6) causing the sheets and the can bodies to push one against the other, also at the
position where step (5) takes place.
The method can be particularly characterized by
7) performing step 4) by welding.
The invention gives preference to a method which is characterized by
8) performing step 5) by applying a coating of a synthetic resin powder;
9) causing said powder to melt, run out and enamel by supplying heat; and
10) causing the thus formed coating to cure by cooling.
The method can for instance be characterized by
11) performing step 5) by applying a coating on the entire inner surface of the successive
bodies.
The method may also be characterized by
12) performing step 5) by applying a coating over the seam of the overlapping zones.
In order to be certain that the critical region of the seam, where a sharp edge is
in any case present, is completely covered by the coating, which is of decisive importance
particularly for food products, the method can be characterized in a preferred embodiment
by
13) performing step 11) in combination with step 12) such that a coating of increased
thickness is situated over the said seam.
A highly effective application of the powder can be ensured by
14) performing step 8) by electrically charging the powder beforehand.
This method can for instance be embodied such that it is characterized by
15) performing step 14) by subjecting the powder to a corona discharge.
In preference however this method is characterized by
16) performing step 14) by guiding the powder along the surface of an isolator.
[0002] For mutually adhering the overlapping portions of the edge zones the device can advantageously
display the feature that the adhering means comprise two co-acting welding rollers,
whereof the first engages on the outside and the second on the inside of said overlapping
portions, which first welding roller is supported by the arm carrying the applying
device.
[0003] Very simple but nevertheless reliable production is ensured with a variant which
has the feature that the overlapping portions are held in position by guide grooves
in a block.
[0004] In an embodiment where the applying device is adapted for applying synthetic resin
powder the device can be further characterized by a heat treatment station for causing
powder to melt, run out and enamel through supply of heat and the thus formed coating
to cure through cooling.
[0005] In a particular embodiment the device may have the feature that the applying means
are arranged for applying a coating on the entire inner surface of the successive
bodies. The device may also have the feature that the applying means are arranged
for applying a coating over the seam of the overlapping zones. It is further possible
for the device to have the feature that the applying means are arranged for applying
a coating on the entire inner surface of the successive bodies and moreover a coating
over the seam of the overlapping zones such that a coating of increased thickness
is situated over the said seam.
[0006] For applying powder with great homogeneity and reliability over the entire surface
for coating the device can be characterized by a charging station for electrically
charging powder to be applied.
[0007] Use can be made for this purpose of corona means or of an isolator surface, along
which the powder for applying is guided, at an interval from which surface is located
a conductor surface with earth connection for draining charge. In this latter case
the device can be characterized by at least one tube of an insulating material, for
instance PTFE (polytetrafluoroethylene) and a conductor for connection to earth arranged
close fitting around it.
[0008] The device preferably displays the feature that via a conducting, for instance carbonaceous,
medium such as a paste the isolator has a connection externally to metal, for example
aluminium, for connection to earth. Hereby ensured is an effective charging of the
powder in addition to a rapid draining of the static charge formed in the isolator.
[0009] The invention also relates to a can body manufactured with the method according to
the invention in addition to a can with such a body.
[0010] The invention offers a number of important advantages. Compared to processes with
wet lacquer a considerable energy saving is possible, namely in the order of 40 to
60%. The process according to the invention enables lacquer standardization. According
to the invention, applying of the coating to successive objects takes place in a fluent,
continuous movement relative to the applying station. The process therefore requires
only one production line.
[0011] The invention will now be elucidated with reference to the annexed drawing, wherein:
Fig. 1 shows a partly broken away schematic perspective view of a first part of a
device according to the invention, wherein the can bodies are made from sheets;
Fig. 2 shows a view corresponding with fig. 1 of a second part of the device according
to the invention shown therein, wherein the can bodies are provided internally with
a layer of powder;
Fig. 3 and 4 show respectively the details III and IV of fig. 1 in cross section on
enlarged scale;
Fig. 5 shows a view corresponding with fig. 2 of a variant which is arranged for also
applying an additional layer of powder on the seams of the can bodies;
Fig. 6 is a partly broken away perspective view of the welding station;
Fig. 7 is a partly broken away perspective view of the spray nozzle on enlarged scale;
and
Fig. 8 shows on enlarged scale a perspective view of one of the single charging tubes
according to fig. 7.
[0012] Fig. 1 shows a device 1 for manufacturing metal can bodies with an internal coating.
Device 1 comprises a stock holder 2 wherein a stack of metal sheets 3 is arranged.
By means of a take-off member 4 the bottom sheet 3 is removed each time from the stack
and guided in the direction of arrows 5 through a cracking station 6 in which the
sheet is rid of residual stresses by light bending in opposing directions.
[0013] After leaving the cracking station 6 the relevant sheet is bent round by means of
bending rollers 7 to the rounded shape designated 3'. The dimensioning of device 1
is such that the leading edge 8 of the bent round sheet 3' is arranged in a guide
groove 9 in a guide block 10. This is shown in more detail in fig. 3. The trailing
edge 11 is arranged in a second guide groove 12 of block 10.
[0014] After the described tangential in-feed an axial transport is performed in the direction
of arrows 13 by means of carrier fingers 114 and guide rails 115.
[0015] The tangential in-feed and axial transporting are carried out around an arm 14 which
serves to bear a welding roller 15 and a spray nozzle 22, 23 (see also fig. 2 and
5).
[0016] The bending of sheets 3' by the rollers 7 takes place such that the edges 8, 11 press
through the tension of the sheets 3' themselves against the bottoms of the guide grooves
9, 12. These grooves gradually increase in depth in the direction of arrows 13 as
will be apparent from comparing figures 3 and 4. The leading edge 8 and trailing edge
11 of sheets 3' are thus placed in overlap such that after leaving block 10 they can
be welded fixedly to one another by the above mentioned internal welding roller 15
and an external welding roller 16.
[0017] An electric power unit 17 is connected via a power supply cable 18 to the outer welding
roller 16 and via a power supply cable 19 to the inner welding roller 15. The cable
19 extends through the arm 14.
[0018] The arm 14 is supported by a frame 20 and is also arranged to encase diverse lines,
at least one of which can be connected to a reservoir for powder which has to be applied
in a manner to be described hereinafter to the inner surface of the can bodies to
be manufactured by device 1. The relevant powder line can also be connected to a source
of medium under pressure, in particular compressed air, for transporting and distributing
the powder.
[0019] In this embodiment the mentioned spray nozzles 22 and 23 according to fig. 2 and
5 respectively form a cardan coupling with the end of the arm 14. The guiding of the
can bodies 3' in the vicinity of the welding rollers 15, 16 is performed by means
of freely rotating rolls 24, the guiding function of which is taken over in the region
of the spray nozzles 22, 23 by guide ropes 25. An encasing 26 serves via a suction
line 27 to draw off excess powder at the position of the spray nozzles 22, 23.
[0020] The positioning of the spray nozzles 22, 23 is carried out by external rolls 28 which
are supported via the meanwhile finished, i.e. fixedly welded, can bodies 3'' by means
of rolls 29 present on the end of the nozzles 22, 23. Attention is drawn to the fact
that the guiding by the ropes and rolls has to take place such that undesired variations
of position are prevented. Three sets of rolls for instance, distributed over the
underside of the periphery, are sufficient in practice.
[0021] The spray nozzles 22, 23 distribute the powder 30, electrically charged in a manner
to be further described, homogeneously over the inner surface of the finished can
bodies 3''. A homogeneous application of a coating consisting of powder hereby takes
place. As a result of the electrical charge transferred to the powder 30 this powder
30 adheres well to the relevant inner surface.
[0022] As fig. 2 shows, the spray nozzle 22 delivers the powder 30 at its extremity 31.
[0023] The variant according to fig. 5 also comprises a slot-like powder delivery opening
32 which is arranged on top of the spray nozzle 23 and which is provided on its side
edges with brushes 33. The opening 32 delivers a directed jet of electrically charged
powder 30 for applying a coating over the seam 34 of the said overlapping zones of
the can bodies 3'', namely the leading edge 8 and the trailing edge 11. The spray
nozzle 23 thus first performs an application of powder onto the seam 34 and then applies
a layer of powder homogeneously over the whole inner surface. Thus achieved is that
a coating of increased thickness is situated over the said seam 34.
[0024] By means of a heat treatment station (not drawn) placed downstream of the spray nozzle
22, 23 is achieved that by supplying heat the powder 30 present on the inner surface
of the can bodies 3'' melts, runs out and enamels, and can subsequently cure through
cooling.
[0025] In this latter respect it is pointed out that applying a coating according to the
invention can be carried out not only by making use of powder but use can also be
made for instance of liquid means.
[0026] Means for electrically charging the powder are arranged in the spray nozzles 22,
23.
[0027] Use can for instance be made of a high-voltage transformer which receives its supply
via the arm 14 and the frame 20. One of the mentioned lines 21 can therefore provide
such a supply. A high-voltage transformer can be arranged in the spray nozzles 22,
23.
[0028] The embodiments of the invention discussed here are equipped however for charging
the powder 30 by means of triboelectricity. Fig. 7 shows the spray nozzle 22. This
comprises eight charging tubes 35 for electrically charging powder 30 passed through
at great speed according to arrows 36.
[0029] Fig. 8 shows such a charging tube 35. It comprises a PTFE tube 37, an intermediate
tube 38 arranged therearound which is conducting because it contains carbon and, arranged
around this latter, an aluminium tube 39 which is connected to earth 40 for draining
static charge. This structure is capable of charging the powder 30 through electrokinesis
or frictional electricity to a voltage in the order of 40-80 kV, whereby a very effective
coating of the powder on the inner surface of the can bodies 3'' is ensured.
[0030] With regard to welding together of the edges 8 and 11 of the bent sheets 3' for forming
the can bodies 3'' it is noted that at the location of the welding operation these
sheets 3' and the bodies 3'' may not lie adjoining each other so as to avoid electrical
short circuit. Use is made in practice of a mutual interval of several millimetres.
It will be apparent that this is requirement is not necessary beyond the welding station
and that particularly in the applying of the powder it could even be advantageous
if the bodies 3' processed there were to lie at least practically adjoining, since
this could possibly stimulate the effectiveness of the application of the powder.
[0031] No attention is paid in the figures and description to control and measuring elements,
such as temperature sensors, which can form part of the device.
[0032] The invention offers a method and a device enabling can bodies with internal coating
to be manufactured with very simple means from metal sheets in one processing run.
The performing of an additional manufacturing step, particularly the applying of a
lacquer layer, is no longer necessary according to the invention. In the embodiment
of fig. 5 the critical seam can be provided with an extra coating, while the rest
of the surface is provided with the single, thinner layer. This is an advantage compared
to the prior art, wherein the layer thickness must always correspond with the required
relatively great layer thickness for covering a seam. On the one hand a cost saving
can be realized, while on the other hand a better quality can also be ensured.
1. Method for manufacturing metal can bodies (3') comprising the steps of:
1) providing metal sheets (3) of which the width is a little greater than the periphery
of a can body (3') and the length corresponds to the height of a can body (3');
2) transporting successive sheets (3) in lengthwise direction;
3) bending the sheet metal transversely of the lengthwise direction of the path such
that the edge zones (8, 11) mutually overlap;
4) mutually adhering the overlapping portions of the edge zones (8, 11);
characterized by,
5) applying an internal coating on these bodies using an applying device carried by
an arm, which extends in lengthwise direction from a region located upstream of the
region were the edge zones (8, 11) are made to overlap.
2. Method as claimed in claim 1,
characterized by
6) causing the sheets (3) and the can bodies (3') to push one against the other, also
at the position where step (5) takes place.
3. Method as claimed in claim 1,
characterized by
7) performing step 4) by welding.
4. Method as claimed in claim 1,
characterized by
8) performing step 5) by applying a coating of a synthetic resin powder (30);
9) causing said powder (30) to melt, run out and enamel by supplying heat; and
10) causing the thus formed coating to cure by cooling.
5. Method as claimed in claim 1,
characterized by
11) performing step 5) by applying a coating on the entire inner surface of the successive
bodies (3').
6. Method as claimed in claim 1,
characterized by
12) performing step 5) by applying a coating over the seam (34) of the overlapping
zones.
7. Method as claimed in claims 5 and 6,
characterized by
13) performing step 11) in combination with step 12) such that a coating of increased
thickness is situated over the said seam.
8. Method as claimed in claim 4,
characterized by
14) performing step 8) by electrically charging the powder (30) beforehand.
9. Method as claimed in claim 8,
characterized by
15) performing step 14) by subjecting the powder (30) to a corona discharge.
10. Method as claimed in claim 8,
characterized by
16) performing step 14) by guiding the powder (30) along the surface of an isolator.
11. Device (1) for performing the method as claimed in any of the foregoing claims for
manufacturing metal can bodies (3'), which device comprises:
- conveyor means (4, 6, 114) for feeding metal sheets and carrying away can bodies
(3');
- bending means (7) for bending the sheets (3) transversely of the conveying direction
during feeding thereof such that the edge zones (8, 11) are placed and held in overlap;
and
- adhering means (15, 16) for mutually adhering the overlapping portions of the edge
zones (8, 11) for forming of successive can bodies (3');
characterized by,
- an applying device (22, 23) for applying an internal coating on these bodies, which
applying device (22, 23) is carried by an arm (14) which extends in lengthwise direction
from a region located upstream relative to the adhering means (15, 16).
12. Device as claimed in claim 11, characterized in that the adhering means comprise two co-acting welding rollers (15, 16), whereof the first
(16) engages on the outside and the second (15) on the inside of said overlapping
portions, which first welding roller (16) is supported by the arm (14) carrying the
applying device (22, 23).
13. Device as claimed in claim 12, characterized in that the overlapping portions are held in position by guide grooves (9, 12) in a block
(10).
14. Device as claimed in claim 11, characterized in that the applying device (22, 23) is adapted for applying synthetic resin powder.
15. Device as claimed in claim 14, characterized by a heat treatment station for causing powder to melt, run out and enamel through supply
of heat and the thus formed coating to cure through cooling.
16. Device as claimed in claim 11, characterized in that the applying means (22, 23) are arranged for applying a coating on the entire inner
surface of the successive bodies.
17. Device as claimed in claim 11, characterized in that the applying means (32) are arranged for applying a coating over the seam (34) of
the overlapping zones.
18. Device as claimed in claims 16 and 17, characterized in that the applying means (22, 23, 32) are arranged for applying a coating on the entire
inner surface of the successive bodies (3') and moreover a coating over the seam (34)
of the overlapping zones such that a coating of increased thickness is situated over
said seam (34).
19. Device as claimed in claim 14, characterized by a charging station (35) for electrically charging powder (30) to be applied.
20. Device as claimed in claim 19, characterized by corona means (35).
21. Device as claimed in claim 19, characterized by an isolator (37) surface, along which the powder (35) for applying is guided, at
an interval from which surface is located a conductor (38) surface with earth (40)
connection for draining charge.
22. Device as claimed in claim 21, characterized by at least one tube (37) of an insulating material, for instance PTFE (polytetrafluoroethylene)
and a conductor (38) for connection (40) to earth arranged close fitting around it.
23. Device as claimed in claim 22, characterized in that via a conducting, for instance carbonaceous, medium such as a paste the isolator
(37) has a connection externally to metal (39), for example aluminium, for connection
(40) to earth.
1. Verfahren zum Herstellen metallischer Behälterteile (3'), mit folgenden Schritten:
1) Metallbleche (3) werden bereitgestellt, deren Breite etwas größer als der Umfang
eines Behälterteils (3') ist und deren Länge der Höhe eines Behälterteils (3') entspricht;
2) Bleche (3) werden nacheinander der Länge nach herangeführt;
3) das metallische Blechmaterial wird quer zur Längsrichtung des Pfades so gebogen,
daß sich die Randabschnitte (8, 11) überlappen;
4) die sich überlappenden Teile der Randabschnitte (8, 11) werden aneinander befestigt;
dadurch gekennzeichnet, daß
5) auf die Behälterteile eine Innenbeschichtung aufgetragen wird, wozu eine von einem
Arm getragene Beschichtungseinrichtung verwendet wird, wobei sich der Arm in Längsrichtung
erstreckt ausgehend von einem Bereich, der dem Bereich vorgelagert ist, in welchem
die Randabschnitte (8, 11) zur Überlappung gebracht werden.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß
6) dafür gesorgt wird, daß die Bleche (3) und die Behälterteile (3') sich gegenseitig
schieben, und zwar auch an der Stelle, an welcher der Schritt 5) erfolgt.
3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß
7) der Schritt 4) durch Schweißen erfolgt.
4. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß
8) der Schritt 5) erfolgt, indem eine Beschichtung aus Kunstharzpulver (30) aufgetragen
wird;
9) das Pulver (30) durch Zufuhr von Wärme dazu gebracht wird, zu schmelzen, zu zerfließen
und zu emaillieren; und
10) die dadurch gebildete Beschichtung durch Abkühlen zum Aushärten gebracht wird.
5. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß
11) der Schritt 5) erfolgt, indem eine Beschichtung auf der gesamten Innenfläche der
aufeinanderfolgenden Behälterteile (3') aufgetragen wird.
6. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß
12) der Schritt 5) erfolgt, indem eine Beschichtung auf der Nahtlinie (34) der sich
überlappenden Abschnitte aufgetragen wird.
7. Verfahren nach den Ansprüchen 5 und 6, dadurch gekennzeichnet, daß
13) der Schritt 11) in Kombination mit dem Schritt 12) in der Weise erfolgt, daß auf
der Nahtlinie eine Beschichtung erhöhter Materialstärke aufgetragen wird.
8. Verfahren nach Anspruch 4, dadurch gekennzeichnet, daß
14) der Schritt 8) erfolgt, indem das Pulver (30) zuvor elektrisch geladen wird.
9. Verfahren nach Anspruch 8, dadurch gekennzeichnet, daß
15) der Schritt 14) erfolgt, indem das Pulver (30) einer Koronaentladung ausgesetzt
wird.
10. Verfahren nach Anspruch 8, dadurch gekennzeichnet, daß
16) der Schritt 14) erfolgt, indem das Pulver (30) entlang der Oberfläche eines Isolators
geführt wird.
11. Vorrichtung (1) zur Durchführung des Verfahrens nach einem der vorhergehenden Ansprüche
zum Herstellen metallischer Behälterteile (3'), wobei die Vorrichtung folgende Merkmale
aufweist:
- eine Fördereinrichtung (4, 6, 114) zum Zuführen von Metallblechen und zum Abführen
von Behälterteilen (3');
- eine Biegeeinrichtung (7) zum Biegen der Bleche (3) quer zu der beim Zuführen herrschenden
Förderrichtung, dergestalt daß die Randabschnitte (8, 11) in gegenseitige Überlappung
gebracht und in dieser Lage gehalten werden; und
- eine Verbindungseinrichtung (15, 16) zum gegenseitigen Verbinden der sich überlappenden
Bereiche der Randabschnitte (8, 11), um dadurch nacheinander Behälterteile (3') zu
bilden;
gekennzeichnet durch
- eine Beschichtungseinrichtung (22, 23) zum Auftragen einer Innenbeschichtung auf
diese Behälterteile, wobei die Beschichtungseinrichtung (22, 23) von einem Arm getragen
ist, der sich in Längsrichtung erstreckt ausgehend von einem Bereich, welcher der
Verbindungseinrichtung (15, 16) vorgelagert ist.
12. Vorrichtung nach Anspruch 11, dadurch gekennzeichnet, daß die Verbindungseinrichtung
zwei zusammenwirkende Schweißrollen (15, 16) aufweist, wobei die erste Schweißrolle
(16) an der Außenseite und die zweite Schweißrolle (15) an der Innenseite der sich
überlappenden Abschnitte angreift und die erste Schweißrolle (16) an dem die Beschichtungseinrichtung
(22, 23) tragenden Arm (14) gelagert ist.
13. Vorrichtung nach Anspruch 12, dadurch gekennzeichnet, daß die sich überlappenden Abschnitte
durch in einem Block (10) angeordnete Führungsnuten (9, 12) in ihrer Lage gehalten
werden.
14. Vorrichtung nach Anspruch 11, dadurch gekennzeichnet, daß die Beschichtungseinrichtung
(22, 23) ausgebildet ist, Kunstharzpulver aufzutragen.
15. Vorrichtung nach Anspruch 14, gekennzeichnet durch eine Wärmebehandlungsstation, die
ausgebildet ist, das Pulver durch Zufuhr von Wärme schmelzen, zerfließen und emaillieren
zu lassen und die somit gebildete Beschichtung durch Abkühlung aushärten zu lassen.
16. Vorrichtung nach Anspruch 11, dadurch gekennzeichnet, daß die Beschichtungseinrichtung
(22, 23) ausgebildet ist, eine Beschichtung an der gesamten Innenfläche der aufeinanderfolgenden
Behälterteile aufzutragen.
17. Vorrichtung nach Anspruch 11, dadurch gekennzeichnet, daß die Beschichtungseinrichtung
(32) ausgebildet ist, eine Beschichtung auf der Nahtlinie (34) der sich überlappenden
Abschnitte aufzutragen.
18. Vorrichtung nach den Ansprüchen 16 und 17, dadurch gekennzeichnet, daß die Beschichtungseinrichtung
(22, 23, 32) ausgebildet ist, eine Beschichtung an der gesamten Innenfläche der aufeinanderfolgenden
Behälterteile (3') und zusätzlich auf der Nahtlinie (34) der sich überlappenden Abschnitte
in der Weise aufzutragen, daß auf der Nahtlinie (34) eine Beschichtung erhöhter Materialstärke
gebildet wird.
19. Vorrichtung nach Anspruch 14, gekennzeichnet durch eine Ladestation (35) zum elektrischen
Aufladen von aufzutragendem Pulver (30).
20. Vorrichtung nach Anspruch 19, gekennzeichnet durch eine Korona-Entladungseinrichtung
(35).
21. Vorrichtung nach Anspruch 19, gekennzeichnet durch eine Isolatoroberfläche (37), an
der das aufzutragende Pulver (30) entlanggeführt wird, wobei in einem Abstand zu der
Isolatoroberfläche eine geerdete (40) Leiteroberfläche (38) zum Ableiten von Ladung
angeordnet ist.
22. Vorrichtung nach Anspruch 21, gekennzeichnet durch wenigstens ein Rohr (37) aus isolierendem
Material, zum Beispiel PTFE (Polytetrafluorethylen), und einen eng um das Rohr (37)
herum angeordneten Leiter (38) zum Anschluß (40) an Erde.
23. Vorrichtung nach Anspruch 22, dadurch gekennzeichnet, daß der Isolator (37) über ein
leitfähiges, zum Beispiel kohlenstoffhaltiges Medium, wie etwa eine Paste, eine Verbindung
nach außen an Metall (39), zum Beispiel Aluminium, zum Anschluß (40) an Erde aufweist.
1. Procédé de fabrication de corps de boîtes en métal (3'), comprenant les étapes suivantes
:
1) fourniture de feuilles en métal (3) dont la largeur est légèrement supérieure à
la périphérie d'un corps de boîte (3') et dont la longueur correspond à la hauteur
d'un corps de boîte (3') ;
2) acheminement des feuilles (3) successives dans le sens longitudinal ;
3) cintrage de la feuille en métal de façon transversale à la direction longitudinale
du parcours, de telle sorte que les zones de bordure (8, 11) se recouvrent l'une l'autre
;
4) fixation l'une sur l'autre des parties des zones de bordure (8, 11) se recouvrant
;
caractérisé par
5) l'application d'un revêtement intérieur sur ces corps en utilisant un dispositif
d'application porté par un bras, qui s'étend dans le sens longitudinal à partir d'une
zone située en amont de la zone où les zones de bordure (8, 11) sont amenées à se
recouvrir.
2. Procédé selon la revendication 1, caractérisé par
6) le fait d'entraîner les feuilles (3) et les corps de boîtes (3') à se pousser les
uns les autres, également au niveau où l'étape (5) est mise en oeuvre.
3. Procédé selon la revendication 1, caractérisé en ce que
7) l'étape 4) est mise en oeuvre par soudage.
4. Procédé selon la revendication 1, caractérisé en ce que
8) l'étape 5) est mise en oeuvre par application d'un revêtement en poudre (30) de
résine synthétique ;
9) le fait de faire fondre, s'écouler et fusionner la poudre (30), est réalisé par
apport de chaleur ; et
10) le revêtement ainsi formé est durci en le faisant refroidir.
5. Procédé selon la revendication 1, caractérisé en ce que
11) l'étape 5) est mise en oeuvre en appliquant un revêtement sur toute la surface
intérieure des corps (3') successifs.
6. Procédé selon la revendication 1, caractérisé en ce que
12) l'étape 5) est mise en oeuvre en appliquant un revêtement sur la jointure (34)
des zones se recouvrant.
7. Procédé selon les revendications 5 et 6, caractérisé en ce que
13) l'étape 11) est mise en oeuvre en combinaison avec l'étape 12) de telle sorte
qu'un revêtement d'épaisseur plus importante est présent au-dessus de la jointure.
8. Procédé selon la revendication 4, caractérisé en ce que
14) l'étape 8) est mise en oeuvre en chargeant électriquement, au préalable, la poudre
(30).
9. Procédé selon la revendication 8, caractérisé en ce que
15) l'étape 14) est mise en oeuvre en soumettant la poudre (30) à une décharge en
effet corona.
10. Procédé selon la revendication 8, caractérisé en ce que
16) l'étape 14) est mise en oeuvre en guidant la poudre (30) le long de la surface
d'un isolateur.
11. Dispositif (1) de mise en oeuvre du procédé selon l'une quelconque des revendications
précédentes, destiné à produire des corps de boîtes en métal (3'), dispositif qui
comprend :
- des moyens de transport (4, 6, 114) destinés à l'alimentation en feuilles de métal
et au transport des corps de boîte (3') ;
- des moyens de cintrage (7) destinés à cintrer les feuilles (3) de façon transversale
par rapport au sens de transport lors de la fourniture de celles-ci, de telle sorte
que les zones de bordure (8, 11) sont placées et maintenues dans une position où elles
se recouvrent ; et
- des moyens de fixation (15, 16) destinés à fixer l'une à l'autre les parties des
zones de bordure (8, 11) se recouvrant, pour la formation des corps de boîtes (3')
successifs ;
caractérisé en ce qu'il comporte :
- un dispositif d'application (22, 23) destiné à l'application d'un revêtement intérieur
sur ces corps, dispositif d'application (22, 23) qui est porté par un bras (14) qui
s'étend dans le sens longitudinal à partir d'une zone située en amont par rapport
aux moyens de fixation (15, 16).
12. Dispositif selon la revendication 11, caractérisé en ce que les moyens de fixation
comprennent deux cylindres de soudage (15, 16) coopérants, dont le premier (16) s'applique
sur l'extérieur et le deuxième (15) s'applique sur l'intérieur des zones se recouvrant,
le premier cylindre de soudage (16) étant supporté par le bras (14) portant le dispositif
d'application (22, 23).
13. Dispositif selon la revendication 12, caractérisé en ce que les zones se recouvrant
sont maintenues en place par des rainures de guidage (9, 12) ménagées dans un bloc
(10).
14. Dispositif selon la revendication 11, caractérisé en ce que le dispositif d'application
(22, 23) est adapté à l'application de poudre de résine synthétique.
15. Dispositif selon la revendication 14, caractérisé par un poste de traitement thermique
destiné à faire fondre, s'écouler et fusionner la poudre, par apport de chaleur, et
à faire durcir le revêtement ainsi formé par refroidissement.
16. Dispositif selon la revendication 11, caractérisé en ce que les moyens d'application
(22, 23) sont conçus pour appliquer un revêtement sur toute la surface intérieure
des corps successifs.
17. Dispositif selon la revendication 11, caractérisé en ce que les moyens d'application
(32) sont conçus pour appliquer un revêtement sur la jointure (34) des zones se recouvrant.
18. Dispositif selon les revendications 16 et 17, caractérisé en ce que les moyens d'application
(22, 23, 32) sont conçus pour appliquer un revêtement sur toute la surface intérieure
des corps (3') successifs et, en outre, un revêtement sur la jointure (34) des zones
se recouvrant, de telle sorte qu'un revêtement d'épaisseur plus importante soit présent
au-dessus de la jointure (34).
19. Dispositif selon la revendication 14, caractérisé par un poste de mise en charge (35)
destiné à charger électriquement de la poudre (30) destinée à être appliquée.
20. Dispositif selon la revendication 19, caractérisé par des moyens à effet corona (35).
21. Dispositif selon la revendication 19, caractérisé par une surface isolante (37), le
long de laquelle la poudre (35) destinée à être appliquée est guidée, surface à distance
de laquelle est située une surface conductrice (38), avec une mise à la terre (40)
destinée à capter la charge.
22. Dispositif selon la revendication 21, caractérisé par au moins un tube (37) en matériau
isolant, par exemple du PTFE (polytétrafluoroéthylène) et un conducteur (38), destiné
à la mise à la terre (40), disposé de façon serrée autour de lui.
23. Dispositif selon la revendication 22, caractérisé en ce que, grâce à un moyen conducteur,
par exemple carboné, tel qu'une pâte, l'isolateur (37) est relié de façon externe
au métal (39), par exemple de l'aluminium, pour la mise à la terre (40).