FR2534878A1 - METHOD AND MACHINE FOR SHAPING CARDBOARD PACKAGING TRAYS, AND TRAY THUS OBTAINED - Google Patents

Abstract

1. Packing tray of corrugated cardboard, of the type comprising a base 12, two longitudinal walls 14, two transversal walls 16 higher than the transversal walls and each terminating at its ends in two angular returns 18, two horizontal entablatures 20 advancing parallel to the base from horizontal upper edges of the transversal walls, and two independent reinforcement sheets 24 applied against the transversal walls and designed to increase the resistance to "bundling" of the ends of the tray or the heads 28 which are defined between the base and the entablatures, the said tray being characterized by the fact that the reinforcement sheets 24 are held in position by reason of the fact that their horizontal edges fit into grooves 34 approximately equal in thickness to the reinforcement sheets and formed by compressing the cardboard along folding lines by which the lateral walls 14, 16, are articulated to the base and to the entablatures, the said reinforcement sheets having for this purpose a height 1 substantially equal to the internal height, h, of the transversal walls 16 puls the sum of the depths of the two grooves 34 into which each of them is fitted.

Description

-1- Method and machine for shaping packaging trays

carton, and thus obtained tray.

  The present invention relates to improvements in corrugated cardboard packaging trays, which are commonly used for the packaging and display of

  fresh products, such as fruits and vegetables.

  It is recalled that such trays include a bottom, two longitudinal walls, two transverse walls of height greater than that of the longitudinal walls and two horizontal entablings advancing parallel above the bottom from the upper edge of the transverse walls These entablings are therefore elevated relative to the longitudinal walls and thus allow their stacking without damaging the products they

  contain and a good aeration of these.

  In the rest of the description, we will designate each

  terminal portions of the plate which include entablatures.

  During transport and exposure of the trays filled with products and stacked in piles, the heads of trays are subjected to compressive forces beyond a certain threshold, which depends of course on the position of the tray in the stack , the density of the packaged products as well as their degree of humidity, the transverse walls of the trays may flare up or soften while losing their strength Moreover, during their transport from the production sites to points of sale , the piles of trays work under the action of repeated and sudden shocks, which contributes to further weaken the resistance of the heads of trays. To improve the strength of the trays and their resistance to stacking, it is certainly possible to use a material that is stronger than paperboard, but this results in relatively expensive trays, which necessarily results in an increase in the price of the tray.

sale of packaged products.

  French Patent No. 2,267,958 has thus proposed a fruit tray which, in the developed state, comprises a fonld which is extended at each of its longitudinal ends by a tab on which are glued, before the setting of the volume. plateau,

  plates intended to form the two transverse walls of the plate.

  These plates are made of a relatively rigid material, such as wood, chipboard or double-sided corrugated board The bonding of the two plates before forming the tray, obviously introduces an appreciable delay in the production cycle and

  slows down the rate of production.

  According to another known method, the trays of the type under consideration are reinforced by introducing corrugated cardboard reinforcing plates inside the tray heads after the shaping of the tray, with the same surface as that of the internal faces of the plates.

  transverse walls and applied against them.

  Thus doubled, the transverse walls should have a better resistance to stacking, but in reality, there is practically no improvement in resistance, since when they are inserted into the heads, the pads are deformed slightly along their edge Thus, up to a given compression force, only the transverse walls of the plate participate in the resistance to stacking Most often, this given force is greater than the buckling force of the transverse walls, so that when the central portion undeformed platelets intervene, the transverse walls are already deformed At this time, the weight of the trays of the pile is no longer supported only by the reinforcing plates which in turn end up flaming Thus instead of adding their resistance to give the tray a double resistance against stacking, the transverse walls of the tray and the plates The result is that with such a process, the plate is practically not reinforced. Moreover, in this method too, the placing of the reinforcing plates in the finished plate introduces a delay in the cycle of

manufacture of the tray.

  The present invention aims to remedy all these drawbacks and proposes for this purpose a method of setting up volume packaging trays said reinforced heads, from a cardboard plate properly cut and grooved to form a bottom, two walls longitudinal, two transverse walls of height greater than that of the longitudinal walls, each ending at its ends by two return angles, and two horizontal entablings advancing parallel to the bottom from the upper limit of the transverse walls , said method being characterized in that it consists in laying flat the cardboard plate in the developed state, to stand perpendicularly to the plate, along the folding lines of the transverse walls on the bottom, two reinforcing plates of surface slightly greater than the internal section of the tray 9, then to fold successively around the plates, the transverse walls, entablatures and angle returns to bring them to their normal position, the plates then being pinched, all along their edge

  peripheral, between the falling flanks of the fold lines.

  Thus, for the fixing of reinforcement plates, the well known fact is that in a fold line, the board is reduced to a very small thickness so that when the board is folded at 900, the side flanks of The folding line is practically applied one on the other. This allows the use of surface-reinforcing boards higher than the internal section of the heads of the board, since the edges of the boards can be housed between the re-entrant flanks. This result is unexpected since at first glance one would tend to use lower surface reinforcement boards or at most equal to the inner section of the tray heads. In an advantageous embodiment of the invention, grooves of thickness substantially equal to that of the reinforcing plates are printed on the starting cardboard plate and the tray caome is shaped in this case also. peripheral edge of the pads is fitted into the grooves, so that upper surface plates can be used

  at the internal section of the tray heads.

  The advantage of the method according to the invention lies in the fact that the platelets are put in place during the operation mm & e of setting volume of the cardboard plate contrary to the methods reported above in which the platelets are introduced after the coup. initially, the plates are applied against the inner face of the transverse walls without risk of deformation, unlike known methods in which the

  pads are put in place after the tray has been mounted.

  Thanks to the method according to the invention, the plates hold in place of them-males, without it being necessary to glue or staple them on the transverse walls of the plate In addition, they exactly double the surface of said walls and participate because of this, the resistance to stacking, whatever the constraints

exercising on the trays.

  Another subject of the present invention is a device for implementing this method. A conventional device is used for this purpose designed for shaping the head trays, for example that described in the French patent application no. O 79 02 484, to which some modifications are made to

  adapt it to the volume of trays with reinforced t tates.

  It will be recalled first of all that the device for making the volume of cardboard plates according to this patent comprises a mobile unit consisting of two horizontal and parallel punches of section equal to the internal section of the heads and which are articulated by means of connecting rods. arranged in the form of articulated parallelograms, on a base which is driven by an alternating linear movement between an upper position for which the punches are in contact with

  the cardboard plate to be shaped and a lower position-

  for which the punches are released from the plate.

  It follows from this provision that when no obstacle -ne is present in their path, the punches move in block with the base and that, otherwise, while the base continues its vertical movement, the punches are move horizontally by moving apart or moving closer to each other

depending on the position of the obstacle.

  The improvement according to the invention lies in the fact that in the lower position of the crew, the set of punches and rods is in the collapsed position, the external vertical faces of the punches then being located respectively exactly below the fold lines of the two walls. transversely on the bottom of the cardboard plate, and respectively flush with outlet openings of two fixed reinforcing pad supply magazines, and said external vertical faces are provided with gripping means capable of grasping the first plate of each store in order to position it under the fold line of the corresponding transverse wall on the bottom of the plate and to release it only when the heads of the tray have been

formatted.

  The gripping means may for example be constituted by a vacuum source which sucks the plates through openings formed on said outer faces of the punches. So that the punches are positioned exactly in front of the store openings, appropriate centering means may be provided. In a particular embodiment, the latter comprise at least one patch attached to said external faces of the punches and which, when the punches are correctly centered, comes to fit into an obviously complementary shape

formed on platelets.

  The pads can be made of any rigid or semi-rigid material, for example corrugated cardboard, cardboard, chipboard, plywood, molded plastic, isorel, etc. They can have extremely varied shapes In their simplest embodiment they have a rectangular shape of dimensions greater than those of the transverse walls of the plate, with possibly on their edges cutouts corresponding to the cutouts existing on the heads of the plate They can also extend in the longitudinal direction by two lateral flaps intended for s' apply against the longitudinal walls of the tray. Such a plate in the form of a double dihedral provides reinforcement

  increased plateau in the corners of the heads.

  Other features and benefits will appear in the

  following description of various forms of

  platelets according to the invention and a machine for setting up

  In this description, reference should be made to

  FIG. 1 is a perspective view of a head packaging tray equipped with reinforcing plates. FIG. 2 is a plan view of a plate for the production of the tray according to FIG. FIG. 3 shows a sectional view, on an enlarged scale, according to FIG. III-III of FIG. 1 FIG. 4 is a partial sectional view of an alternative embodiment of the packaging tray FIGS. 5 to 7 show three possible forms of reinforcement platelets; Figures 8 to 10 show in section a forming machine tray, in three successive phases of its operation; and Fig. 11 is a partial perspective view of

the machine according to the invention.

  Referring first to Figure 1 which represents a

  fruit platter 10, says to heads.

  This plate comprises a rectangular bottom 12, two longitudinal walls 14, two transverse walls 16 terminated at each end by angle returns 18 which are secured to the inner face of the longitudinal walls 14 by gluing or stapling, and two raised entablatures 20 , contiguous to the walls

  transverse and forming a step forward over the bottom and -

  parallel to it The entablatures are terminated at their ends by flaps 22 which are applied to the returns

  18 and are secured, for example by gluing.

  To improve the stacking strength of such a plate, rectangular reinforcing plates 24 similar to

that shown in Figure 4.

  As explained above, the plates 24 are -posed perpendicular to the cardboard plate 10 in the developed state (FIG. 3), by making one of their longitudinal edges coincide with the folding ligia 26 of the transverse walls.

  16 on the bottom 12 Then we turn up to 90 the walls -

  transverse to the bottom, then the angle returns 18 and entablatures 22 are folded to bring them into the position they

have in Figure 1.

  As can be seen in FIG. 2, the plate 24 has a width 1 greater than the internal height h of the head of the plate 28. From its height, its length is greater than the internal length of the plate head 11. when the carton is folded, the flanks 30, 32 of the fold lines pinch the edges of the wafers, thus keeping them in place, without the need to glue or staple them on the walls

transversal 16.

  In the variant embodiment illustrated in FIG. 4, grooves 34 of width substantially equal to the thickness of the reinforcing plates 24 are printed on the carton along the fold lines which surround the transverse walls 16. The edges of the inserts are nested in said grooves, so that the

  pads are securely held in place.

  The plate 24 of FIG. 5 is rectangular and may have on its longitudinal edges the same cutouts as those

  transverse walls 16 of the tray.

  The plate of FIG. 6 comprises a central portion 24 and two lateral flaps 36 intended to be applied against the transverse wall 16 and the shutters 18 of the plate, thus conferring

  plate heads increased strength.

  In the plate of Figure 6, pan-shaped portions

  cut 38 are provided between the central portion 24 and the flaps 36.

  These sections 38 are placed obliquely in the corners and ensure that

  makes even better resistance of the tray heads.

  With reference to FIG. 7, the tray forming machine comprises a crew 39 which can move vertically and alternatively under the action of motor means not shown. This crew comprises a horizontal base 40 carrying two identical sets of two vertical flat flanges 42, 44

arranged in rows of two.

  On each of the flanges 42, 44 are articulated the ends of two identical and parallel links, respectively 46, 48 and 50, 52, whose other ends are hinged on parallelepipedal hollow punches 54, 56, of substantially complementary section to that of the The bielettes 46, 48 are crossed with the links 50, 52, each of said pairs of links forming a deformable hinged parallelogram. The axes of articulation of the links on the flanges

  and on the punches are horizontal and parallel.

  In the lower position of the crew (FIG. 8) the rods 46, 48, 50, and 52 are in a horizontal, collapsed position, the external faces 58, 60 of the punches then being at a mutual distance equal to the distance separating the In this position, the faces 58, 60 are respectively flush with the openings of two magazines 62, 64 each containing a stack of reinforcing plates 24 in a vertical position. Said external faces 58, 60 are pierced with orifices. 68 on which the end of the pipes 70, 72 connected to a source of vacuum are fitted on the inside of the punches. As shown in FIG. 11, on the outer faces of the punches are placed centering pellets 74 intended to fit into complementary indentations 76 formed on

  the longitudinal edges of the plates 24.

  The operation of the machine will now be described: at the beginning of a cycle, the machine is in the state shown in FIG. 7 A cardboard plate 10 in the developed state is brought into a centered position, above the machine. movable element 39 with its folding lines facing downwards, and it is held stationary in this position by stop means not shown The moving assembly 39 is in its lower position for which its punches 54, 56 are spaced and are respectively flush with the openings of the magazines 62, 64 The punches-54, 56 are correctly centered in front of the opening of the magazines thanks to the pellets 74 which engage in the indentations 76 The depression which is exerted through the orifices 68 maintains the first plate 24 of each

  store applied against the adjacent punch.

  The moving element 39 then rises en bloc under the solicitation of the motor means, causing movement in their movement the two sucked plates 24 When the punches 54, 56 arrive at their upper position, the upper edges of the plates are in contact with each other.

  contact with fold lines 26.

  Torsion elements 80 and 82 are then straighten around the plates and punches, the transverse walls 16 and longitudinal 14, the angle returns 18, the entablatures 20 and the flaps 22 As shown in Figure 9, the plates 32 are thus pinched all along their peripheral edge between the transverse walls 16 and the lips of the fold lines

surrounding them.

  The vacuum 40 is then cut off so as to separate the plates 24 from the punches. The base 40 then initiates its downward movement. In this movement, the punches 54, 56 approach by sliding on the internal faces of the entablatures 20 which are maintained. by the folding elements 82 When the punches are completely free of entablatures 20, they are free

  to accompany the base 40 in its downward movement (Figure 10).

  Under the effect of the own weight of the punches, the rods 46, 48, 50, 52 return to their initial horizontal position of FIG. 8, the punches being connected tangentially to the openings

some stores.

  The plateau can then be evacuated to make way for a

other flan.

  Figure 10 shows a particular embodiment of a wafer supply magazine 24 The magazine comprises four horizontal rods 84, 86, 88, 90 arranged so that the wafers can rest there for their notches 76 The rods hold so the pads and guide them in their movement towards the opening of the store It goes without saying that the stores

  \ may have any other appropriate configuration.

  Note that in a stack of trays filled with products, the upper trays support a very low weight These trays may not be reinforced For this, the tray shaping machine may include means that put out of service the source of vacuum as soon as the stack of trays formed has a predetermined number of trays.

  moment, the punches will no longer support platelets.

12-

Claims (9)

  1. Corrugated cardboard packaging tray, of the type comprising a bottom (12), longitudinal walls (14), two transverse walls (16) of height greater than that of the longitudinal walls and which each end at its ends by two angle returns (18), two horizontal entablings (20) advancing parallel to the bottom from the upper edge of the transverse walls, and two plates (24) applied against the transverse walls (16) and intended to reinforce the stacking resistance of the tray ends or heads (28) which are defined between the bottom and the entablatures, said tray being characterized in that the pads have a surface slightly greater than the internal section of the tray heads, and that their peripheral edges are pinched between the inward flanks of the fold lines that   surround said transverse walls.   2. Packaging tray according to claim 1, characterized in that the fold lines which surround the transverse walls are constituted by grooves of thickness substantially equal to that of the reinforcing plates, and in   which join the edges of the latter.   3. Method of setting the volume of the packaging tray according to   one of claims 1 and 2, characterized in that it consists of   lay flat the cardboard plate (10) in the developed state, to stand perpendicularly to the plate, along the fold lines (26) of the transverse walls on the bottom, two reinforcement plates (24) of slightly greater surface at the inner section of the tray heads (28), then successively folding around the plates, the transverse walls (16), the entablatures (20) and the angle returns (18) to bring them to their normal position, the platelets then being pinched, all along their peripheral edge, between the falling flanks of the fold lines.   4. Machine for the implementation of the method according to claim 3, of the type comprising a movable element (39) consisting of two horizontal and parallel punches (54, 56) of section equal to the internal section of the heads (28) and which are articulated, by means of rods (56, 48, 50, 52) arranged in the form of articulated parallelograms, on a base (40) which is driven by a linear reciprocating movement between an upper position for which the punches are in contact with the cardboard plate (10) to be shaped and a lower position for which the punches are disengaged from the plate, said machine being characterized in that in the lower position of the crew (39), the punch and rods is in a collapsed position, the external vertical faces (58, 60) of the punches being respectively located exactly below the fold lines (26) of the two transverse walls (16) on the bottom (12) of the pl at least one cardboard plate and flush respectively with outlet openings of two fixed reinforcing pad supply magazines (62, 64), and in that said external vertical faces are provided with gripping means (70, 72) capable of to enter the first plate (24) of each magazine to position it under the fold line (26) of the corresponding transverse wall (16) on the bottom (12) of the plate and to release it only when the heads of the tray have been shaped. 5. Machine according to claim 4, characterized in that the gripping means are constituted by a vacuum source which sucks the plates through openings (68) formed on   said outer faces (58, 60) of the punches. -14-   6. Machine according to one of claims 4 and 5, characterized   in that the punches are provided with centering means enabling them to be positioned correctly facing the openings of the   stores, when in the low position.   7 Machine according to claim 6, characterized in that said centering means are constituted by elements (74) attached to the outer face (58, 60) of the punches (54, 56) and which are capable of fitting into one another. notches (76) forées on the reinforcing plates.   Machine according to one of Claims 4 to 7, characterized   in that the magazines (62, 64) are each constituted by horizontal rods arranged so that the reinforcing plates   (24) can be supported by their indentations (76).   9. Machine according to one of claims 4 and 5, characterized   in that it comprises means capable of putting out of action the gripping means as soon as the stack of trays coming out   of the machine comprises a predetermined number of trays.