FR2577530A1 - Egg box with lid, its manufacturing method and mould implementing this method - Google Patents

Abstract

This box, intended for the grouped packaging of several eggs, comprises a bottom 1 with cells 3, provided at its upper part with hooks 5 for the retention of a closing lid. The hooks 5 are constituted by a sheet of thin material extending that of the cellular bottom 1, 3 and limited by a sharp edge 8, under which is formed a window 9. The cut-out of these windows 9 associated with the various hooks 5 is produced during the manufacturing process of the cellular bottom 1, 3 by thermoforming.

Description

I "Egg box with lid, manufacturing process and mold for

the implementation of this process "

  The present invention relates to an egg box, for packaging

  lage grouped of several eggs. More particularly, this invention relates to devices for closing egg boxes of the com- type.

  bearing a honeycomb bottom and provided, at its upper part, with beaks or hooks

  chets for the adaptation of a closing cover, the honeycomb bottom

  being produced by thermoforming and cutting a sheet material.

  In the closing devices for egg boxes of this type, with bottom formed by thermoforming, the spouts or hooks form,

  on the bottom, growths which cannot be removed from the mold directly-

  ment, hence the need to use special molds. Thus, molds are used with drawers which are complex and expensive, but which above all do not make it possible to house the mechanisms allowing a tray formed for example of four boxes of six eggs to be produced in a single operation. We must therefore produce these boxes in pairs, instead of

  four, leading to increased manufacturing and packaging costs-

  ment. There are also molds with parts retracting by

  rotation, but for small beaks or hooks these parts are fragile.

  In addition, the current shapes of the spouts or hooks, obtained by thermoforming, are very rounded where a retention of the cover

  by clipping which is not always very effective.

  The present invention aims to eliminate all these drawbacks, by providing a closure device with spouts or hooks which is more economically feasible, whatever the number and position of the spouts or hooks, while allowing locking

  improved cover on the bottom.

  To this end, the invention essentially relates to an egg box with cover, of the type defined above, in which the spouts

  retaining cover, located above or at the cutting plane

  page of the thermoformed sheet, consist of a veil of thin material extending that of the honeycomb bottom and limited by a sharp edge under which a window or light is formed, a flat support surface

  for the cover being present at the base of said window or light.

  More particularly, in the case of an egg box, the honeycomb bottom of which is greater than the largest dimension of the eggs, which allows it to be closed by a cover of planar shape,

  the cover retaining spouts are formed above the peripheral rim

  risk of the honeycomb bottom, constituting said planar bearing surface, the windows

  very arranged between the sharp edges of the spouts and the peripheral rim

  than. The beaks are for example formed, at least at the four corners of the honeycomb bottom, by a veil of material directly extending the side wall of a honeycomb and limited towards the outside by a sharp edge,

  under which is the window.

  The shape of the spouts, with a sharp edge, allows effective retention by clipping the cover, which rests on the rim

  peripheral or other flat surface present at the base of each spout.

  Of course, the cover has openings or other conforma-

  tions allowing its clipping, by engagement under the spouts and in the windows associated with the spouts, provisions that can be provided

  in addition to make the packaging tamper-proof.

  The particularly suitable conformation of the cover retaining spouts is advantageously obtained, without falling material or

  recovery operation, therefore very economically, during the process

  thermoforming itself allowing obtaining the shape of the honeycomb bottom and its peripheral cutting, this by a cutting carried out in the zones corresponding to the spouts, this cutting giving

  birth to the windows or lights associated with these beaks.

  By this original manufacturing process, all operations are eliminated.

  rework that it would have been necessary to perform, with the technique

  conventional thermoforming, to obtain perpetual windows or lights

  dicular to the general cutting plane, which greatly limits costs. This is in particular obtained by making cuts in the sheet material at the time of pinching thereof by its zone corresponding to the periphery of the honeycomb bottom to be produced, before the operation.

thermoforming proper.

  The invention also relates to a thermoforming mold

  specially intended for the implementation of this process. The mold

  takes, in a known manner, a bottom of shape corresponding to that of the honeycomb bottom to be produced, a matrix displaceable relative to the bottom for the initial nipping of the sheet and for the subsequent peripheral cutting, a preforming punch and blowing means for pressurized air. The mold base has protruding parts, intended for the formation of spouts, which have cooperating cutting edges.

  with auxiliary punches also with cutting edges, the punches

  auxiliary cons being linked to the cutting die but able to describe a certain movement relative to this die, in the direction of the opening-closing movement of the mold. When closing the mold, each punch driven by the die cooperates, by its edge

  of cutting, with the cutting edge of the bottom part of the corresponding mold

  in front of the spout, to cause the cut giving rise to the window or light, the dimensions of which are perfectly controllable thanks

  the arrangement of the mold parts.

  In any case, the invention will be better understood using

  the description which follows, with reference to the appended schematic drawing representing

  feeling, by way of nonlimiting examples, an embodiment of

  this egg box as well as a variant, and illustrating how it is made

  cation. Figure 1 shows, in perspective, an egg box according to the present invention, without its cover Figure 2 is a plan view from above of this egg box Figure 3 is a side view, with half-section along III- III of Figure 2; Figure 4 is a sectional view along IV-IV of Figure 2, passing through one of the cover retaining spouts;

  Figure 5 shows a variant of the egg carton according to the invention.

  tion, in perspective and with the cover separate from the bottom; Figures 6,7,8 and 9 are sectional views, very schematic, illustrating the successive phases of the combined forming and cutting process to obtain the honeycomb bottom of the egg carton according to the invention; Figures 10 and II are partial detail views, in section, of the thermoforming mold in two separate positions, explaining

  3 (j the formation of the region of a beak, with cutting of the window.

  The egg carton, a first embodiment of which is shown in Figures 1 to 4, generally consists of a honeycomb bottom

  (1) and a cover (2), the latter not being shown in FIG.

  1. The bottom (1), made of thermoformed plastic, here comprises six cells (3) designed to receive six eggs, and it has a higher height. ive to the largest dimension of eggs. The closure is thus achievable by means. a flat cardboard cover (2). The bottom (1) has, at its top, a peripheral rim (4) facing outwards. At the four corners of the rim (4) are formed nozzles (5), facing outwards, intended for the attachment of the cover (2). In the center of each group of four cells (3) arranged in a square is formed a stud (6). The top of each stud (6) is flush with the plane of the rim (4) and has a lug (7), allowing it to be retained

  complementary to the cover (2) in its central region.

  The present invention relates more particularly to the realization

  tion of the cover retaining nozzles (5) (1). Each spout (5) is constituted by a veil of thin material, extending directly upwards the side wall of the cell (3) located at the same angle. This spout (5) is limited towards the outside by a sharp edge (8), under which is located

  a window or light (9), also cut in the rim (4).

  The cover (2), indicated in phantom in Figures 2 and 3, has openings (10) towards its four corners, for example in the form of circular holes, through which the nozzles (5) are introduced, which ensures a effective retention of the cover (2) on the bottom (1) by clipping effect. It should be noted that the cover (2) can also, contrary to what is shown here, not exceed the outline

  outside of the peripheral rim (4) of the bottom (1).

  In a variant, illustrated by FIG. 5, the bottom (1) is produced

  by a cardboard base (11) glued to a plastic half-shell

  that (12), which forms for example cells (3) intended to receive two eggs, the depth of these cells (3) being substantially equal to half of the largest dimension of the eggs. The cover (2) is formed by another plastic half-shell, different from the first but still having conformations (13) intended to partially receive the eggs. The locking of the cover (2) on the bottom (1) is always obtained by means of protrusions in the form of spouts (5), produced at the top of the lower half-shell (12) and cooperating with counterparts such as circular holes (10) from

  the upper half-shell. The spouts (5) are here located at inter-

  medians of the length of the box, and not at the angles, but their conformation remains entirely similar to that described above in

reference to Figures I to 4.

  Figures 6 to 11 illustrate the method of manufacture, by combined forming and cutting, of the bottom (1) of the egg carton according to the figures

  I to 4, with its spouts (5). The tools used, shown very schematically-

  ment to Figures 6 to 9, is a thermoforming mold composed of a bottom (14), a cutting die (15) and a preforming punch (16). The cutting die (15) is movable relative to the mold base (14) so as to allow the closing or opening of the mold, as well as the cutting operation. The punch (16) is itself

  movable relative to the die (15).

  The mold is initially opened, as shown in the figure

  6, to allow the lateral introduction of a sheet of plastic material

  that (17), from which will be formed and cut a bottom of an egg box.

  The first phase then consists in tarnishing! E moldp "-v-ppronemhnt of the matrix (15) and the bottom (14), until a pinching of the sheet (17) is carried out with sealing, so as to allow the

  compressed air supply - see figure 7.

  Then, the preforming punch (16) is lowered, to stretch the material of the sheet (17) in the direction of the bottom (14) of the mold. The compressed air is sent inside the mold, as indicated by arrows (18), so as to apply the material of the sheet (17) against the bottom walls (14), in order to achieve the finish of the article in him

  giving the exactly desired shapes - see figure 8.

  In the next phase, the cutting die (15) is moved

  created relative to the bottom (14) so as to separate the molded article,

  forming the bottom (1) of the egg carton, of the rest of the sheet (17) -

  see figure 9. Finally, the mold is opened, the article produced is extracted

  and ejected by known means, and a new cycle identical to the previous one

tooth can start.

  The formation of the spouts (5) and of the associated windows (9) is carried out during the process described above, without the need for any recovery operation, using the means represented in the figures and II which show the detail of the preceding mold, in a region

  corresponding to an angle of the honeycomb bottom to be produced.

  We thus find in these Figures 10 and 11 the die (15), with its cutting edge (19) which cooperates with a cutting edge (20) of the mold base (14) to cut the periphery of the article to be produced. The mold base (14) still has a projecting part (21) whose profile corresponds to that of the spout (5 to be fferrmer, at each corner of the article. The projecting part (21) has motmwnm i

  a cutting edge (22), facing outwards.

  Each protruding part (21) is associated with an amLxw're punch (23), linked to the matrix (15) but which can describe a certain mmuvemremit

  relative to this matrix, in the direction of the movement of minrure-

  closing the mold. This movement is limited downwards by a bearing face (24) of the matrix (15), facing upwards. ô '): can be lifted above this face - apnui (24), at l'Ilesmontie

  of the action of a spring call or ersin jack call cons-

has, not represents. -

  When closing the mold, the cutting edge C2M & Ira part (21) of the bottom (14) of profile corresponding to the spout 5, merwe a complementary edge (25) belonging to the punch (23), prnuanmt

  in this place a cutout. The mold ends its movement of & nrmetu-

  re, to ensure the pinching of the sheet (17) between the edges mspec-

  tives (19,20) of the matrix (15) and the bottom (14), and allows the (qp & a-

  conventional preforming, blowing and cutting 'riïlarige

  described above - see figure 10.

  When the sheet (17) is pinched between the edges (9,2El ", the

  bottom (14) and the punch (23) block the material of this f e6 m-

  opposite faces (26,27 28g, 29), so as to control the dimensions of the window (9) which will have as height the dimension N! [e of the face (30) situated under the cutting edge ( 22), and as it widen lia

  length of this cutting edge (22).

  The punch (23), maintained until now in support oim li face (24) of the matrix (15) thanks to the rk ri qy return system with constant pressure cylinder, will then go back under Pacfim from the bottom rise (14), the matrix (15) not being moved, so as to allow general cutting of the article (1) at its perieter, enle

  the two cutting edges (19,20) - see figure 11.

  When the mold base (14) descends to allow the exrac-

  tion of the article, the punch (23) comes to rest on the ae (24)) ile the matrix (15), and thus occupies a position allowing the cmunenmeTment

  of a new cycle identical to the previous one.

  It goes without saying that the invention is not limited to the sole embodiments of this egg box and of the means for its manufacture which have been described above, by way of examples; she embraces it,

  on the contrary, all the variants of implementation and application respectively

  both the same principle. In particular, one would not depart from the scope of the invention by turning the cover retaining spouts inwards or by giving them any other angular orientation, or by making them with a greater length, or else by changing their number and / or their position, depending on the shape and dimensions of the bottom of the box, which may have more or less cells

many., -

Claims (8)

  1. Egg box, of the type comprising a honeycomb bottom (1,3) and provided, at its upper part, with beaks or hooks (5) for the adaptation of a closure cover (2), the honeycomb bottom ( 1,3) being produced by thermoforming and cutting a sheet material (17), characterized in that the nozzles (5) for retaining the cover (2), located above or at the cutting plane of the thermoformed sheet, are   formed by a veil of thin material extending that of the honeycomb bottom   width (1,3) and limited by a sharp edge (8) under which a window or light (9) is formed, a flat surface (4) bearing for the cover   (2) being present at the base of said window or light (9).   2. Egg box with cover according to claim 1, of the kind of which the honeycomb bottom (1,3) is higher than the largest dimension of the eggs, the cover (2) being of planar shape, characterized in that that the cover retaining nozzles (5) (2)   are formed above the peripheral rim (4) of the honeycomb bottom, constituted   killing said planar bearing surface, the windows (9) being formed between   the sharp edges (8) of the spouts (5) and the peripheral rim (4).   3. Egg box with lid according to claim 2, character-   in that the spouts (5) for retaining the cover (2) are formed, at least at the four corners of the honeycomb bottom (1,3), by a veil of material directly extending the side wall of a honeycomb (3) and limited towards the outside by a sharp edge (8), under which is the window (9).   4. Method for manufacturing an egg carton according to any one   as in claims 1 to 3, in which the shape of the honeycomb bottom (1,3)   is obtained from a sheet material (17) by a process of thermoforming and peripheral cutting, characterized in that is carried out during this process, in the zones corresponding to the spouts (5), an additional cutting giving birth in windows   or lights (9) associated with the spouts (5) for retaining the cover (2).   5. Method of manufacturing an egg carton, according to the claim   tion 4, characterized in that the cutouts, giving rise to the windows or lights (9), are made in the sheet material (17) at the time of pinching thereof by its zone corresponding to the periphery (4) of the bottom honeycomb (1,3) to be produced, before the thermoforming operation proper.   6. Thermoforming mold for implementing the method of manufacturing an egg carton according to claim 5, of the type comprising a bottom (14) of shape corresponding to that of the honeycomb bottom (1, 3) to be produced, a matrix (15) movable relative to the bottom (14) for the initial nipping of the sheet (17) and for the subsequent peripheral cutting, a preforming punch (16) and means for blowing compressed air (18), characterized in that the mold base (14) has projecting parts (21) intended for the formation of the spouts (5), which have cutting edges (22) cooperating with auxiliary punches (23) also with cutting edges cut (25), the auxiliary punches (23) being linked to the cutting die (15) but which can describe a certain   movement relative to this matrix (15), in the direction of the movement   opening-closing mold.   7. Thermoforming mold for the manufacture of an egg carton according to claim 6, characterized in that each projecting part (21) of the bottom of the mold (14), intended for the formation of a spout (5), has under its cutting edge (22) a face (30) whose height determines that of the window (9) associated with the spout (5), the length of the window (9) being determined by the length of this cutting edge (22).   8. Thermoforming mold for the manufacture of an egg carton according to claim 6 or 7, characterized in that the movement of each auxiliary punch (23) relative to the cutting die (15) is limited in one direction by a bearing face (24) of said matrix (15), the movement considered being against the action of a   spring return or constant pressure cylinder return system.