OBJECT OF THE INVENTION
[0001] The present invention relates to a seal for cans, especially for preserves, like
for example of asparaguses, tomato, peppers, etc., of any configuration, and obtained
from tinplate, aluminium, or any other material suitable for this purpose, the objective
being to facilitate considerably the operation of opening said cans, without detriment
to the sealing properties in themselves, insofar as the conservation of the content
thereof is concerned, and with a total absence of risk during the opening manipulation.
BACKGROUND OF THE INVENTION
[0002] As it is well known, conventional preserve cans are structured by means of a body,
from sheet iron suitably treated both externally and internally, which body can adopt
a prismatic, cylindrical or other configuration, and which in all cases after being
filled, receives over their mouth a sealing cover, also metallic, of similar characteristics,
which is flange mechanically on the aforementioned mouth determining, as well as an
airtight seal, a rim usable in the later opening operation, as a means of support
for the classic can opener.
[0003] This opening problem becomes worse in the preserve cans that contain fruit of considerable
size like asparagus, not only for its larger size, but also because the form thereof,
based on a succession of noticeably curved straight segments, create problems both
for these last-mentioned segments both when the opening is carried out with a manual
can opener and when it is carried out with an electric one.
[0004] One of the solutions that has been given for the difficulty or inconvenience of opening
preserve cans, has been the use of "easy-open" cans, in which the cover comes, in
the vicinity of the aforementioned rim, with a stamp determining a weakened line that
allows relatively easy opening, by ripping, to which effect the detachable sector
of the cover has an associated ring, usable initially as the means to initiate the
tear and immediately thereafter as opening puller.
[0005] This solution has been applied to all types of can, cylindrical, rectangular and
oval. Although it allows quicker opening of the can, it presents on the other hand,
a problem which is centred fundamentally on two aspects, on one hand on many occasions
breaking of the opening ring occurs, rendering the system unusable, and on the other
hand and much more frequently, when the material employed is tin, cuts are produced
in the hands and/or fingers of the users, due to said tinplate constituting the detachable
sector of the cover, during the opening operation, presents a very sharp cutting edge.
[0006] This problem could be resolved partly by the use of aluminium cans, but this solution
would imply a significant increase in cost in that, for storage and transport requirements,
this type of can is stacked up to very considerable heights and, since the mechanical
strength of aluminium is considerably less than that offered by tinplate for an identical
can cost, a noticeable increase would be necessary in the thickness of wall thereof
to avoid the crushing of those that occupy the lower layers or a higher cost which
is not always accepted by the market because canned products are not usually products
of high unit price.
[0007] Furthermore, it is necessary to bear in mind that the canning process of certain
fruits, like asparagus for example, involves sterilization in which the cans are subjected
to a temperature of up to 120° C in sterilizers which work under pressure that counteracts
the interior outward pressure produced by the content of the can as a consequence
of the heating thereof.
DESCRIPTION OF THE INVENTION
[0008] The seal for cans that the invention proposes resolves in a fully satisfactory manner
the problem explained above in the two commented aspects, assuring an extraordinarily
quick and easy opening and without the least risk of harm for the user, and likewise
taking advantage of the form of sterilization which certain fruits undergo.
[0009] In brief, then, the invention in a can for preserves of any configuration which,
for example, in the case of asparagus adopts a rectangular form, with its corners
rounded wherein one of its larger faces has been stamped or hollowed and substituted
in its greater part by an aluminium and plastic film which is easily pealed away.
[0010] To this end and in more specifically, the invention centers upon substituting most
of the classic rigid cover of the can, based on treated sheet metal, by a stratified
lamina based on an aluminum and plastic composite, of those already in use in the
foodstuffs industry, although with other different applications.
[0011] The substitution of part of the cover by means of the stamping thereof leaves the
edge thereof uncovered, which remains in contact with the internal content thereof.
[0012] It is consequently necessary to solve the problem that is posed by the nature of
conserving liquid in the case of preserves, because it is composed, mainly, of water
and salt. Such a composition proves highly corrosive for the iron of which the can
is made and which, on rim that is produced by the stamping of the cover, is not coated
with the resin that coats the rest of the interior of the container, protecting it
from corrosion.
[0013] This problem has been solved satisfactorily by means of implementing upward shoulder
or flange. This flange, at the time of fabricating the cover, determines a small hole
which is filled with the interior coating of the cover and of the can, and which impedes,
together with the shoulder formed, that the conserving liquid comes into contact with
the rim of the stamped cover, avoiding thereby its corrosion.
[0014] In accordance with a first embodiment of the invention, the aforementioned stratified
lamina is supplemented, within the context of the cover, with a frame of metallic
nature, similar to the perimeter area of the cover of a conventional can, said frame
provided with an internal perimeter flange through which is secured thereto, prior
to the seal, the stratified lamina which completes the cover, whereby the cover as
a whole can be coupled to the body of the can with the conventional machinery used
for such in classic preserve cans.
[0015] According to a second embodiment of the invention, the cover comes without the aforementioned
frame, being simply materialized in the stratified lamina that has been mentioned
above, in which case the body of the cannot be conventional but rather must be provided
in its mouth with an internal perimeter flange, similar to that aforementioned for
the frame, with the same purpose of allowing the securing of the stratified lamina.
[0016] In any case, said lamina will be secured either to the frame or directly to the mouth
of the body of the can, by welding or by any other appropriate method which, as well
as a leakproof and stable seal that withstands the sterilization treatment in autoclave,
allows easy opening by means of manual pulling on a fluke, free prolongation of a
point whatever of its contour.
[0017] In any one of the two aforementioned embodiments, either the internal marginal area
of the frame or the marginal area of the mouth of the body of the can, will be turned
upward and outward out so that the rim is conveniently isolated from the interior
recipient, after sealing the can, the object being to avoid problems of oxidation
through said rim being in contact with the conserving liquid, made up of water with
salt, mainly, since for the production of the can, one starts with a metal sheet coated
with a varnish, resin or plastic on the inside to avoid its oxidation, coating element
that obviously does not affect the rim obtained in the stamping operation.
DESCRIPTION OF THE DRAWINGS
[0018] To complete the description that is being made and with the object of assisting in
a better understanding of the characteristics of the invention, in accordance with
a preferred example of practical embodiment thereof, said description is accompanied,
as an integral part thereof, with a set of drawings wherein, by way of illustration
and not restrictively, the following has been represented:
Figure 1. This shows a view in perspective of one of the cans, provided with the seal
which constitutes the object of the present invention.
Figure 2. This shows an exploded and sectional detail of the can of the previous figure,
at the level of its mouth and according to a first embodiment of the invention.
Figure 3. This shows a sectional detail similar to that of figure 3, but corresponding
to the second embodiment of the invention.
Figure 4. This shows a similar can to that of figure 1, in which its lower base has
been implemented by means of a body distinct to that of the side and joined thereto
by means of a flange similar to that of figure 2.
Figure. 5. This shows a view in perspective of other possible configurations that
the cans may adopt.
PREFERRED EMBODIMENT THE INVENTION
[0019] In the light of these figures, more specifically of figures 1 and 2, it can be seen
how the seal that is proposed is applicable to preserve cans obtained from sheet metal,
pressed and suitably treated both internally and externally, to withstand external
environmental effects and those resulting from their own content.
[0020] Now in accordance with the invention, the aforementioned body (1) is completed with
a cover structured by means of a perimeter frame (2) which is secured to the mouth
of the aforementioned body by the conventional flange system, as shown in figure 2,
with the particularity also that in said frame (2) an internal perimeter flange (3)
is defined, preferably included in an imaginary horizontal plane, to which is secured
by welding, by means of adhesive or by any other appropriate means, a stratified lamina
(4) which completes the cover and which will be obtained by means of a classic composite
based on a fine aluminum sheet clad internally with a plastic lamina.
[0021] Clearly the system of securing the cover should offer enough strength to withstand
the sterilization treatment in autoclave, as has been stated previously.
[0022] This stratified lamina (4), which is secured tightly to the flange (3) over the full
length of the latter, will be inserted in the classic recess defined by the rim (2),
except for a fluke (5), prolongation thereof and which constitutes a handle employable
in the opening operation.
[0023] Nevertheless and in accordance with the embodiment variant shown in figure 3, the
possibility exists that the frame (2) is not present, so that the flange (3') is obtained
from the actual body (1) of the can, by means of folding the mouth thereof, securing
the aforementioned stratified lamina (4), as in the previous case, to this flange
(3'), said lamina having likewise the fluke (5) for manual pulling.
[0024] In any one of the two variants mentioned, it is foreseen that the flange (3-3') incorporates
a fold (6) in the marginal area corresponding to its free edge, oriented upward and
outward, as can be observed especially in figures 2 and 3, so that the said free edge
(7) is perfectly isolated from the interior of the can and protected from of the effects
of oxidation by the cover (4) itself. In this sense the fold (6) mentioned should
be implemented, as may also be observed in figures 2 and 3, so that the flange (3-3')
as a whole offers a perfectly flat external surface for a good adaptation of the cover
(4).
[0025] In any case, the can will offer a relatively similar appearance to that of a classic
can, with the only exception that its cover (4) passes from being rigid to being semi-rigid,
maintaining optimum conditions regarding the tightness of the seal and with the outstanding
advantage that its opening is carried out in an extraordinarily quick and simple way,
by means of simple pulling on the fluke (5) and without the least risk of harm for
the user during said opening operation.
[0026] Figure 4 represents a figure similar to 1, but wherein the lower base has been implemented
by means of a body distinct to that of the side (1). This base is joined to the perimeter
and side body by means of an rim (2) similar to that shown in figure 2.
1. Seal for cans, especially for preserves, in which participates a body (1) of any configuration,
based on sheet metal suitable treated both on its external surface and on its internal
surface, characterized in that the cover that completes the body (1) mentioned is materialized in a stratified lamina
(4) of the type of those structured by means of an external layer of aluminum and
an internal layer of plastic which is secured to the mouth of the body by welding,
by means of adhesive or similar, said stratified sheet (4) having a fluke (5), prolongation
thereof, serving as handle during the opening operation.
2. Seal for cans, especially for preserves, according to claim 1, characterized in that the stratified lamina (4) constituting the cover itself is secured to the body (1)
with the collaboration of a rigid metallic perimeter frame (2), of similar nature
to that of the body (1) itself, which frame (2) is firmly coupled to the mouth of
the body (1) by the classic flange system and which incorporates an internal perimeter
flange (3), preferably located in an imaginary horizontal plane to which is secured
the marginal or perimeter area of the stratified lamina (4).
3. Seal for cans, especially for preserves, according to claim 1, characterized in that the stratified lamina (4) constituting the cover itself is secured to the body (1)
through an internal perimeter flange (3'), preferably included in an imaginary horizontal
plane and obtained by means of folding the actual mouth of the container.
4. Seal for cans, especially for preserves, according to previous claims, characterized in that the internal perimeter flange (3) corresponding to the frome (2), as in its case
the perimeter flange (3') obtained by means of having folded the actual mouth of the
container (1), it is provided in its internal marginal area, that determining the
mouth of the can, with a fold (6} oriented upward and outward, so that the rim (7)
of said flange (3-3') is located outside the recepticle defined by the can in sealed
condition and is protected by the stratified sheet (4) itself constituting the cover,
it being foreseen that the aforementioned fold (6) is configured so that the flange
(3-3'), as a whole, offers a perfectly flat upper surface for adaptation of the cover
(4).