FR2659579A1 - METHOD FOR MANUFACTURING HOLLOW ELEMENT AND METAL RECOVERY OF TRONCOPYRAMIDAL FORM AND METAL HOLLOW ELEMENT AND RECIPIENT OF TRONCOPYRAMIDAL FORM. - Google Patents

Abstract

The invention relates to a method of manufacturing a hollow metal element of truncated pyramidal shape according to which: - one cuts out, in a metal sheet, at least one side of rectangular shape, - two opposite edges of said base are brought together in a determined position, so as to form a body of cylindrical shape, - said edges are welded together in said position, - said body of cylindrical shape is shaped so as to obtain a body of truncated pyramidal shape, - a ring is produced on the periphery of said body and close to one end thereof, the concavity of which faces outwardly of said body, the depth of said concavity varying continuously between a maximum value on the short sides of said body up to a minimum value substantially in the center of the two long sides.

Description

The invention relates to shaped metal containers

  trorncopyramidal, consisting of a hollow element and a bottom set on

  this element, especially intended to contain paint.

  The invention relates more particularly to a method of manufacturing a metal hollow element and a metal container, of troncopyramidal shape. It also relates to a hollow metal element and a metal container, of troncopyramidal shape. Various methods of manufacturing containers are known

  which differ in the shape of these receptacles.

  In the case of a cylindrical metal container, the method may consist of cutting metal flanks of rectangular shape into a metal sheet. The cutting is carried out using two circular shears. This cutting process is the most economical because it optimizes both the use of the raw material (thin metal sheet) by minimizing the cutting waste, the cost of cutting labor by optimizing the rates and cost of cutting. the investment of the machine used. The process then consists in welding the cylinder obtained by bringing two opposite sides of the rectangular side together, with a slight overlap and parallel to the axis of the cylinder thus formed. The curling is then carried out at least at one end of the cylinder. flaring so as to obtain a regular flanged edge This flanging step makes it possible to prepare the crimping of the bottom which is carried out in a last step and makes it possible to obtain the tightness of this crimp between the flanging steps and the crimping, a molding of container body can possibly

to be realized.

  There is also known a method of manufacturing containers

conical shaped metal.

  As for the cylindrical metal container, the method consists of cutting rectangular sidewall and proceed to its welding so as to obtain a cylindrical body is then formed the body permanently deforming the cylindrical body, to the With the aid of an expansion tool acting along the axis of the cylinder and mounted on a suitable machine, this forming makes it possible to

  to obtain a conical shaped body.

  The process continues as before by a step of flanging and crimping the bottom, the possible molding of the body can be performed during the forming step, with the same expansion tool. It is conceivable to make a metal container of tronco-pyramidal shape by a process similar to that to obtain a conical metal container It would be sufficient to use, during the forming step, an expansion tool

  allowing to obtain a body of troncopyramidal shape.

  Such a method, however, has disadvantages.

  The forming step of the cylindrical body makes it possible to deform the cylindrical body so as to give it a truncopyramidal shape, but also causes a camber or a bending of the metal, in the plane of each of the four faces of the truncated pyramid-shaped body. This method does not therefore make it possible to obtain a regular edge on the ends of the body. This entails risks of poorly performing the crimping of the bottom of the container.

  therefore risks of leakage when the container is filled.

  This disadvantage can be overcome by shearing the truncopyramidal body to eliminate bending.

  However, it entails additional operations that are costly.

  It is also possible to stretch the truncopyramidal body in the corners. This requires two operations.

  additional, which is also expensive.

  It is also conceivable to perform a narrowing in the corners of the truncopyramidal body This reduces the body section and eliminate bending This technique has drawbacks however The main disadvantage is the risk of hurting the metal in the corners and to cause the deterioration of the protective layer covering the inner part of the container, thereby causing risks of corrosion during the use of the container. It can furthermore be noted that the depth of the

  shrinkage is technologically limited.

  One can also mention an old process originally designed especially for corned beef boxes This process involves cutting into a sheet of metal a complex shaped flank using a press This flank has the form of a portion of circular crown o alternating ropes and arcs is then proceeded to the welding of the truncated cone obtained by bringing the two portions of radius of the sidewall, with a slight overlap Then proceed to the formation of this truncated cone, so to obtain a truncated pyramid The curling is then carried out at least at one end of this truncated pyramid, by flaring. The flanging operation makes it possible to obtain a regular edge, the latter being predetermined by the shape and the dimensions of the flank. metal cutting This step of curling allows to prepare the last step of the process of crimping a bottom

on the lined end.

  It is found that this method has the advantage of allowing to obtain directly a body of troncopyramidal shape having a regular edge on which a bottom can be crimped after the curling step This method however has the disadvantage of causing misuse of the raw material In fact, the cutting in a sheet of metal metal flanks having a shape

  complex causes relatively large waste.

  The object of the invention is to overcome these drawbacks by proposing a method of manufacturing hollow elements or containers of truncopyramidal shape, making it possible to optimize the use of the raw material as well as the number of necessary operations, in order to

  limit the cost of this hollow element or this container.

  The invention thus relates to a method for manufacturing a truncopyramidal hollow metal element according to which: at least one rectangular-shaped flank is cut out from a metal sheet, two opposite edges of said flank are brought into a position determined so as to form a body of cylindrical shape, said edges are welded together in said position, said body of cylindrical shape is shaped so as to obtain a body of troncopyramidal shape, a ring is produced on the periphery of said body and near an end thereof, whose concavity is turned outwardly of said body, the depth of said concavity varying continuously between a maximum value on the short sides of said body to a minimum value substantially at center -4-

from both sides.

  Preferably, the end of said body of truncopyramidal shape near which said ring is formed corresponds to that of

  the weakest cross section.

  The invention also relates to a method for manufacturing a troncopyramidal metal container according to which:

  a hollow truncated metal element is produced

  pyramidal method according to the method just described, flaring is carried out at said end of this element and a bottom of corresponding shape is crimped on said end

lined with this element.

  Also preferably, the planking and the ring are made simultaneously. The invention also relates to a hollow metal element of troncopyramidal shape consisting of a welded metal sheet and having on its periphery and near an end, a rod whose concavity is directed towards the outside of said element, the depth of said concavity varying continuously between a maximum value on the short sides of said element and a value

  minimum substantially in the center of the long sides of said element.

  Preferably, the end of the element near which said ring is located is the one having the smallest cross section. The invention also relates to a metal container of troncopyramidal shape comprising a hollow metal element as just described and a bottom crimped on the end of this

element comprising said rod.

  The invention will be better understood and other purposes, advantages and features thereof will become more clearly apparent on reading

  of the following description of non-limiting embodiments of

  the invention, with reference to the accompanying drawings in which: Figure 1 shows a half-sectional view of a curling device and formation of the rod, in the open position, Figure 2 shows a half-sectional view according to II-II of Figure 1, Figure 3 shows a half-sectional view of the device for curling and forming the rod, in the closed position, Figure 4 comprises Figures 4a and 4b Figure 4 a represents a top view of a truncopyramidal hollow element according to the invention and FIG. 4b is a perspective view of this element; FIG. 5 represents a side view of a shaped container;

troncopyramidal according to the invention.

  The elements common to the different figures will be designated by

the same references.

  The method according to the invention making it possible to obtain a hollow element of truncopyramidal shape consists firstly in cutting, in a sheet of metal, rectangular metal flanks. The dimensions of the flanks are chosen according to those of the troncopyramidal element that it is desired to obtain As for the known processes for obtaining cylindrical metal containers, the cut is preferably made using two circular shears This cutting process is, in fact, the

more economical.

  The cylinder obtained is then welded by bringing together two opposite sides of the rectangular flank, parallel to the axis of the cylinder thus formed Preferably, the two opposite sides of the flank

  rectangular which are close together have a slight overlap.

  As in the known processes for manufacturing conical metal containers, the forming of the cylindrical body obtained is then carried out by deforming it permanently with the aid of an expansion tool acting along the axis of the cylinder and mounted on an adequate machine The expansion tool is chosen such that the forming step provides a truncopyramidal shaped body. As stated above, the truncopyramidal body obtained has no regular edge at any of its ends. Indeed, the forming step causes a bending of the metal in the plane of formation.

  each of the four faces of the body, at both ends of it.

  The method then consists in producing a ring on the periphery of the body of troncopyramidal shape and close to one of the two

extremities of this body.

  As illustrated in FIG. 4, the ring 13 is made along a transversal section of the element 12 of troncopyramidal shape. The concavity of this ring is directed towards the outside.

of the element.

  The depth of this concavity will be fixed according to the camber obtained during the forming operation of the cylindrical body To compensate for this camber, the depth of the concavity is not constant over the entire periphery of the element It varies continuously between a maximum value on each of the two small sides 14, 15 of the element of truncopyramidal shape up to a minimum value substantially in the middle of each of the two long sides 16, 17 of this element. maximum and minimum depth of the concavity and its

  variation will be determined for each given form element.

  It is the excess of metal bound to the camber of the element on each of its ends which serves to form this rod Thus, after this operation, we obtain a truncopyramidal shaped element whose end, near which been formed the rush, presents a

regular edge.

  Can then intervene the curling operation of this end

  of the element, which is made by flaring.

  The embodiment of the anti-camber rod will now be described

  more precisely with reference to Figures 1 to 3.

  Reference 1 designates a body of truncopyramidal shape, as obtained after the cutting, welding and forming operations.

  of this body is designated by the reference 10.

  The tooling for forming the anti-camber rod is designated by the reference 2 It comprises a first part 3 intended to be placed around the body 1 and a second part 4 intended to be placed vis-à-vis the first, to the In particular, these first and second parts 3 and 4 are made in four separate elements. The elements are mobile and are operated by appropriate means, known to those skilled in the art.

not shown in the figure.

  Each of the elements of the first part 3 has a substantially L shape corresponding to a quarter of the body 1, defined by its two axes of symmetry The height of each element is at least a fraction of that of the body 1 The shape of the inner surface 6 of each element corresponds substantially to that of the outer surface of the body 1, so as to marry the shape thereof It is the same for the outer surface 7 of each element of the second

  part 4 facing the inside of the body 1.

  Each element of the first part 3 comprises, on its inner surface 6, a relief imprint 8, corresponding to the shape of the rod that it is desired to make. Each element of the second part 4 has, on its outer surface 7, an indentation. hollow 9 corresponding to the relief imprint 8 of each element of the

first part 3.

  The operation of this tool is as follows The four symmetrical parts of the second part 4 are placed inside the box body, so as to place the recessed impression 9 at the place where it is desired to make the ring Each element of the first part 3 is also placed around the body 1, so that the raised impressions 8 are substantially opposite an indentation 9 of an element of the corresponding second part 4. each element of the first part 3 against the body 1, according to the arrows Fl It also acts on each element of the second part 4 so that they come to press against the body 1 according to the arrows F 2 By acting thus on the first and second parts 3 and 4 according to the arrows Fl and F 2, embossing of the body 1 is performed by the imprint of the anti-camber ring, corresponding to the embossed imprints 8 and recessed 9 This stamping operation ge is more particularly

illustrated in Figure 3.

  FIGS. 1 to 3 also illustrate a preferred embodiment of the method according to the invention, according to which the steps of

  ring forming and curling can be performed simultaneously.

  For this, the tooling for the formation of the anti-camber ring is completed by a third part 5 This third part 5 is also constituted by four symmetrical and movable elements These four elements are maneuvered by any suitable means and known to man The third part has a substantially parallelepipedal shape whose cross section has a surface greater than that of the section located at the end of the can body near which has been formed the rod It also has -8- on any its periphery and a part of its height a recess 11 Each element of this third part 5 is intended to be placed at least partially inside the body 1, as shown in Figure 1 Note that the third part 5 is positioned such that the end, here below, of the body 1, close to which will be or is made the rod, is based on the horizontal part of the recess 11 During the formation of the ring or immediately after, it acts on each element of the third part 5 so as to move in the direction and direction indicated by the arrow F 3 As shown in Figure 3 this operation enables the lower end of the body 1 to be flared towards the outside of the body 1 and to make the curling of

  the lower end of this edge.

  It will be understood that once the forming operations of the anti-scaling rod and the curling of the end of the body 1 are carried out, the different parts of the tooling (3, 4 and 5) are moved in the opposite direction of the arrows F1, F 2 and F 3, in order to be able to remove the truncopyramidal hollow metal element thus formed from the tooling. It can thus be seen that the method according to the invention which has just been described makes it possible to form the anti-camber rod during the curling operation. This makes it possible to remedy the disadvantages caused by the bending of the metal during the formation of the body of troncopyramidal form, without increasing the number of operations to be performed This method therefore allows to limit the cost price of a truncopyramidal metal hollow element It can be seen that even in the case where the planking and the rod are made in two different stages, the method according to the invention remains economical since it makes it possible to remedy the bending of the metal in a single

additional operation.

  The process for producing the troncopyramidal metal container according to the invention consists in producing a truncopyramidal-shaped element according to the process just described, this element having dimensions corresponding to those of the container.

that we wish to obtain.

  Flanging is then performed at the end of

  the element near which has been made the anti-camber ring.

  Curling is carried out by any appropriate means, known to those skilled in the art, which will not be described here in detail. As previously indicated, the pleating may be carried out during the formation of the

  rush with appropriate tools.

  The second step of the process consists in the crimping of a bottom 19 on the end of the element previously bordered. The edge of the truncopyramidal element used being regular, one obtains a

  crimping of good quality, the risks of escape being thus avoided.

  It is understood that one chooses to achieve the curling and crimp the bottom, the end of the element corresponding to that of weaker

  section so that the containers obtained are stackable.

  FIG. 5 illustrates a container 18 obtained by the method which has just been described. This container comprises, near the bottom 19, a rod

13 anti-arching.

  This container may also include a rod 20, at least in the corners, to allow easy separation of previously stacked containers A cover 21 and a handle 22 may also

to be provided.

  The reference signs inserted after the characteristics

  The techniques set out in the claims are for the sole purpose of

  facilitate the understanding of the latter can not in any way have the effect of limiting the invention to particular modes of

  achievements that have just been described.

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Claims (1)

1 A method of manufacturing a truncopyramidal hollow metal element according to which: at least one flank of rectangular shape is cut out of a metal sheet, two opposite edges of said bottom are brought together in a determined position so as to form a body of cylindrical shape, said ends are welded together in said position, said body of cylindrical shape is shaped so as to obtain a body of troncopyramidal shape (1), a ring (13) is produced on the periphery of said body and near an end thereof, whose concavity is turned outwardly of said body, the depth of said concavity varying continuously between a maximum value on the short sides of said body to a minimum value substantially in the center of the two big sides. 2 A method of manufacturing a truncopyramidal hollow metal member according to claim 1, wherein the end of said truncopyramidal body near which is formed said ring corresponds to that of the lower cross section. 3 Method according to one of claims 1 or 2, characterized in that said rod is formed by placing outside said body (1) a first portion (3) whose shape of the inner surface (6) substantially corresponds to that of the outer surface of said body (1) and which has a relief imprint (8) corresponding to the shape of the rod that is desired and placing inside said body (1) a second part (4) ) whose shape of the outer surface (7) corresponds substantially to that of the internal surface of said body (1) and which has a recess (9) corresponding to the relief imprint (8) of the first part (3). ), said first and second parts (3, 4) being placed in such a way that said indentations (8, 9) are substantially opposite each other and then acting on said first and second parts (3, 4) so as to perform the stamping of the body (1) by the impression of said ring (13) corresponding to said indentations (8, 9). 4 Process according to claim 3, characterized in that said first and second parts (3, 4) are made in four separate and symmetrical elements. Process for producing a truncopyramidal metal container according to which: a truncopyramidal hollow metal element (12) is produced according to the method according to one of claims 1 to 4, flaring is effected at said end of this element (12) is crimped a bottom (19) of corresponding shape on said end lined with this element (12). 6 Process according to claim 5, characterized in that the curling is carried out by means of a third portion (5) of substantially parallelepipedal shape whose cross section has a surface greater than that of the section of said end of said body (1), said third part having over its entire periphery and over part of its height a recess (11), by positioning said third part (5) so that said end of said body (1) rests on the horizontal part said recess (11) and acting on said third portion (5) so as to flare outwardly of said body (1) said end of said body. 7 A method of manufacturing a troncopyramidal metal container according to one of claims 5 or 6 wherein the flange and the rod are made simultaneously. Method according to claim 7, characterized in that said first, second and third parts (3, 4, 5) are actuated simultaneously. 9 hollow metal element of troncopyramidal shape consisting of a welded metal sheet and having on its periphery and near an end, a rod (13) whose concavity is directed outwardly of said element (12), the depth said concavity varying continuously between a maximum value on the short sides (14, 15) of said element and a minimum value substantially at the center of the long sides (16, 17) of said element. 12 - truncopyramidal hollow metal element according to claim 9 wherein the end of the element near which is said rod (13) is the one having the smallest cross section.   1 l troncopyramidal metal container comprising a   hollow metal element according to one of claims 9 or 10 and a   bottom (19) crimped on the end of this element (12) having said ring (13).