FR2730214A1 - METAL BOX WITH PARTIAL OPENING, PROCESS FOR MANUFACTURING SUCH A BOX, AND MACHINE FOR IMPLEMENTING SUCH A PROCESS - Google Patents

Abstract

A container end (11) for a container for liquid products having a planar end panel with raised bosses (13a, 13b). The absence of any countersink prevents build up of liquid deposit on the end and the bosses allow the end to be centred for seaming.

Description

"Partial opening metal box, method of
manufacture of such a box and machine for setting
implementing such a process "
The invention relates to a new metal can of the three-piece type, with partial opening, provided with opening means attached to one of the bottoms; the invention relates more particularly to the configuration of such a box making it possible to avoid an accumulation of dried product at the edge of this box, when its content is not consumed in one go.

 The invention also relates to a method and a machine for manufacturing such a metal can.

 Metal cans of the three-part type with partial opening are very widely used for the packaging of liquid food products.

Some boxes with partial opening are more particularly designed to contain concentrated products (milk, fruit juice ...) which are not always consumed in one go, that is to say completely after opening. The methods of manufacturing such boxes are conventional and consist in fixing, in particular by crimping, two bottoms at the ends of a tubular box body. Typically, the box body is generally cylindrical and each bottom is present before crimping, in the form of a bowl with hemmed edge.

This shape facilitates the crimping of the hemmed edge at one end of the box body. One of the bottoms is provided with opening means, typically easy opening means such as for example an opening ring fixed to said bottom, inside a pre-cutting imprint, so as to release a cut in pulling on the ring. Other opening means can be used, such as for example a heat-sealed cover covering a cutout made in said bottom.

 After the first opening, the product is poured by tilting the box. This maneuver results in an accumulation of product at the edge of the bowl, in the immediate vicinity of the crimping bead. It is common that the product is not completely consumed.

After a certain time, this deposit solidifies and takes on an unappetizing, unpleasant or even suspect color for the consumer.

 The invention aims to solve this problem by modifying the shape of the bottom provided with the opening means so as to remove any bowl at the top of the box.

 More specifically, the invention relates to a metal can of the three-part type with partial opening, provided with opening means attached to one of the bottoms, characterized in that this bottom is devoid of a bowl and fixed to an edge of the said can body and in that it comprises at least one relatively flat boss with a centered overall configuration.

 Indeed, the removal of the cup calls into question the crimping process, and the aforementioned boss or bosses have as main function to allow a good centering of the bottom relative to the box body and a good drive, at the time of their assembly.

 The three-piece box defined above is preferably provided with a peripheral constriction at the end where the bottom is attached. This shrinking reduces the bottom price and allows the boxes to be stacked. In addition, it facilitates the implementation of the box manufacturing process.

 The invention also relates in fact to a method of manufacturing a metal can of the three-piece type and with partial opening, characterized in that it consists in conforming a type of bottom with hemmed edge, without bowl, to be practiced at least a boss with an overall configuration centered in such a bottom and in assembling it to a tubular box body using said boss as a means of centering and driving the bottom relative to the edge of said box body with which it is assembled.

 To do this, a counter-mandrel is introduced inside the box body so that the latter bears against the internal wall of said box body near the edge, hence the additional advantage of a body peripheral shrinking box. The movement of the contremandrin is indeed easier inside the box body. The bottom is held between this counter-mandrel and a centering and drive mandrel located outside the box body and axially aligned with said counter-mandrel. I1 includes a centering clearance or the like cooperating with said boss or a set of such bosses. During crimping, by means of a conventional external wheel, the box body is leaned radially against the counter-mandrel.

 The invention also relates to a machine for assembling a tubular box body and a bottom for implementing the method defined above, characterized in that, said bottom being a bottom without bowl provided with minus a boss with a centered overall configuration, it comprises, axially aligned, a counter-mandrel capable of being introduced into the box body as far as the vicinity of an edge thereof so as to be in contact with the internal wall of said body and a centering mandrel shaped to cooperate with said boss in order to center and drive said bottom relative to said box body.

The invention will be better understood in the light of the description which follows, making it possible to better understand the structure and the manufacture of a metal box in accordance with its principle, given solely by way of example and made with reference to the appended drawings in which :
- Figure 1 illustrates a simple blank in which we will define a new type of bottom capable of being assembled to a tubular box body;
- Figure 2 illustrates a first operation performed on this blank;
- Figure 3 illustrates a second operation performed on this blank;
- Figure 4 illustrates the same background, on a smaller scale, seen according to arrow IV of Figure 3;
- Figure 5 illustrates the same bottom provided with opening means;
- Figure 6 illustrates several finished funds stacked on each other for automatic distribution in a crimping machine;
- Figure 7 schematically illustrates the assembly operation of the bottom and the box body;
- Figure 8 schematically illustrates a partial radial section showing a conventional crimping with bowl-shaped bottom;
- Figure 9 illustrates in the same way as Figure 8 the assembly according to the invention;
- Figure 10 is a view similar to Figure 5 illustrating a variant of the opening means; and
- Figure 11 is a view similar to Figure 5 or Figure 10 illustrating an improvement.

 In the example shown, a bottom 11 shaped according to the principle of the invention is obtained from a sheet metal blank (FIG. 1), here with a circular contour whose peripheral edge 12 is hemmed in a manner known per se (figure 2). The preparation of the base differs from a known process in that it does not transform this base into a bowl. On the contrary, there is at least one relatively flat boss 13 with a centered overall configuration (FIGS. 3 and 4). As can be seen more clearly in FIG. 4, according to the example described, the bottom comprises two such symmetrical bosses 13a, 13k separated by a planar diametral zone 15. This planar zone is intended to come substantially level with the edge 16 of the box body 17, after assembly. The box body has a constriction 14 in the vicinity of the edge 16.

 As shown in FIG. 5, the opening means 18 are arranged on this zone 15. More precisely, each boss 13a 13k has a contour defined by an arc of a circle and the cord thereof. The arc of a circle has the same center as the background itself. These two bosses are therefore spaced on either side of a diameter of said bottom, so that said zone 15 on which the opening means 18 are arranged, has the form of a strip, here rectilinear, extending between them. In the example of FIG. 5, the opening means are conventional, they include a pre-cut cavity 19 and an opening ring 20 fixed by a rivet 21 to the bottom wall, inside of the closed limit of said precut footprint. It should be noted that the two bosses 13a, 13b protect the opening means from any risk of catching during handling and from any accidental actuation maneuver.

 In the embodiment of FIG. 10, the opening means 18a comprise a heat-sealed (or otherwise fixed) cover 22 covering a pre-established cutout 23 in said strip. The heat-sealed cap 22 has a tongue 25 allowing opening by detachment.

 In the example of FIG. 11, a protective cap 28, for example made of plastic, is shaped to fit between the two bosses and cover the opening means. These can be either the opening means 18a shown in Figure 10, or those shown in Figure 5, or any other system.

 This cap may include a nesting sole allowing a filling of the cutout 23, after a partial removal of the content. It can be initially sealed at the edge of the box body, at its two ends, which allows the consumer to check the integrity of the product at the time of purchase.

 As shown in Figure 6, funds 11 thus shaped can easily be stacked on each other without risk of jamming. Indeed, the bosses also allow the bottoms to center with respect to each other, the hemmed edges 12 preventing the bottoms from coming into contact with all of their surfaces.

 Figure 7 provides a better understanding of the role of the bosses when assembling the bottom 11 and the boot body 17. As shown, the assembly machine comprises, aligned axially, a counter-mandrel 30 capable of being introduced in the box body 17 to the vicinity of the edge 16 thereof to be in lateral contact with the internal wall of said box body and a centering and drive mandrel 32, outside the box body shaped to cooperate with the boss or bosses 13a, 13b in order to center the bottom 12 relative to the box body. The mandrel has an internal centering clearance 36 (here defining a sort of frustoconical surface), cooperating with all of the bosses to allow perfect centering and driving of the bottom relative to the edge 16 of the box body, prepared for crimping . Thus, during the operation, the box body 17 is held radially by the presence of the internal counter-mandrel 30 and the bottom is maintained between the counter-mandrel 30 and the mandrel 32, being perfectly centered. Under these conditions, the crimping wheel 35 operates according to a conventional operating mode to perform the peripheral stapling between the edge of the bottom and that of the box body. Advantageously, it has been possible to deposit a seal 38 made of elastomeric material inside the bottom, in the vicinity of the edge of the hem. This seal 38 (Figure 9) participates in the sealing of the assembly.

 FIGS. 8 and 9 make it possible to better compare the profiles of the conventional box body (FIG. 8) and of the box body according to the invention (FIG. 9). We see that the bowl 40 of the classic bottom has completely disappeared, which prevents the accumulation of product at the edge of the box.

 As mentioned above, the constriction of the box body is advantageous since the counter-mandrel 30 can move more easily, axially, inside said body. This constriction also makes the box stackable.

 The invention covers any boss configuration allowing good centering and training at the time of crimping.

Claims (10)

 1- Metal can of the three-part type with partial opening, provided with opening means (18) attached to one of the bottoms, characterized in that this bottom (11) is devoid of bowl and fixed to an edge of said body of box (17) and in that it comprises at least one relatively flat boss (13) with centered overall configuration.  2- metal box according to claim 1, characterized in that said bottom comprises two such bosses (13a, 13k), separated by a planar diametral zone (15), substantially level with said edge (16) of said box body, said opening means (18) being arranged in this area.  3- metal box according to claim 2, characterized in that said bosses (13a, 13b) are spaced on either side of a diameter of said bottom and in that said area (15) on which are arranged said means d opening, in the form of a strip extending between the two bosses.  4- canister according to claim 3, characterized in that the opening means comprise a pre-cut imprint (19) and an opening ring (20).  5- canister according to claim 3, characterized in that the opening means comprise a cover (22) heat sealed or otherwise fixed, covering a cutout (23) pre-established in said strip.  6- Metal box according to one of claims 2 to 5, characterized in that it comprises a protective cap (28), for example made of plastic, shaped to fit between said two bosses (13a, 13b) and cover said opening means or a cutout released by the actuation thereof.  7- Metal box according to one of the preceding claims, characterized in that said box body has a peripheral constriction (14) at the end where said bottom is attached.  8- Method of manufacturing a metal can of the three-piece type and with partial opening, characterized in that it consists in conforming a type of bottom (11) with hemmed edge (12), without bowl, to practice at least one boss (13) with an overall configuration centered in such a bottom and for assembling the bottom to a tubular box body using said boss as a means for centering and driving the bottom relative to the edge of said box body with which it is assembled.  9- A method according to claim 8, characterized in that it comprises a step of maintaining said bottom (11) in the assembly position on the corresponding edge of said box body between a counter-mandrel (30) introduced into said body box and bearing against the inner wall thereof in the vicinity of said edge and a centering mandrel (32), outside the box body, axially aligned with said mandrel and having a centering clearance (36) cooperating with said boss or a set of such bosses.  10- Machine for assembling a tubular box body and a bottom for implementing the method according to claim 9, characterized in that said bottom being a bottom without bowl provided with at least one boss (13 ) with a centered overall configuration, it comprises, axially aligned, a counter-mandrel (30) capable of being introduced into the box body as far as the vicinity of an edge thereof so as to be in contact with the wall internal of said body and a centering mandrel (32) shaped to cooperate with said boss in order to center said bottom relative to said box body.