Process for closing a container in metal sheet

Abstract

The container has a tubular body having a peripheral lateral wall provided with an upper end portion and a lower end portion defining an upper retention hook and a lower retention hook to which is double-seamed a lower end wall. An upper end wall is conformed to incorporate a peripheral upper skirt presenting an end edge defining an inverted U shaped upper closure hook to be seated onto the upper retention hook sandwiching an elastic sealing element therebetween. The upper closure hook and the upper retention hook and also a portion of the peripheral upper skirt and a confronting region of the upper end portion are deformed for seaming the upper closure hook onto the upper retention hook and to form, respectively, a retention rib and a retention groove which tightly fits the retention rib.

1 . A process for closing a container in metal sheet, of the type which comprises a tubular body formed by a peripheral lateral wall having an upper end portion and a lower end portion, to which an upper end wall and a lower end wall are respectively affixed, characterized in that it comprises the steps of:
 conforming a metal sheet portion to define the peripheral lateral wall of the tubular body;   conforming the peripheral lateral wall so as to provide, in its upper end portion, an upper peripheral edge which is outwardly and downwardly bent, defining an upper retention hook with a profile in the form of an inverted U; and, in its lower end portion, a lower peripheral edge which is bent to define a lower retention hook;   peripherally affixing the lower end wall to the lower retention hook of the tubular body;   conforming a metal sheet portion to define an upper end wall having a median panel and a peripheral upper skirt which presents an end edge which is outwardly, downwardly and inwardly bent, so as to define an upper closure hook with a profile in the form of an inverted U;   fitting and seating the peripheral upper skirt in the interior of the upper end portion, with the container being empty or already filled with the product, so as to seat the upper closure hook onto the upper retention hook sandwiching an elastic sealing element previously provided between said hooks; and   submitting the upper closure hook and the upper retention hook and also a portion of the peripheral upper skirt and a confronting region of the upper end portion to a simultaneous deformation operation, in order to seam the upper closure hook onto the upper retention hook, compressing the elastic sealing element, and to form at least one outer circumferential retention rib in the peripheral upper skirt and a corresponding inner circumferential retention groove in the upper end portion of the peripheral lateral wall, tightly fitting the retention rib.   
     
     
         2 . The process, as set forth in  claim 1 , characterized in that the upper retention hook, with the profile in the form of an inverted U, is conformed to present an inner lateral leg defined by part of the upper end portion, an arched base leg and an outer lateral leg which is convergent in relation to the inner lateral leg, the upper closure hook, with the profile in the form of an inverted U, being conformed to present an inner lateral portion defined by an upper part of the peripheral upper skirt, an arched base portion and an outer lateral portion which is convergent in relation to the inner lateral portion and internally incorporating an upwardly projecting end flange the fitting of the upper closure hook onto the upper retention hook being made so that the arched base portion of the former is seated onto the arched base leg of the latter, with the elastic sealing element being disposed between said arched base portion and arched base leg, and the seaming of the upper closure hook onto the upper retention hook being made so as to seat the inner lateral portion, the arched base portion and the outer lateral portion of the upper closure hook respectively against the inner lateral leg, the arched base leg and outer lateral leg of the upper retention hook, compressing the elastic sealing element and having the end flange projecting upwardly to the interior of the upper retention hook, between the outer lateral leg and the inner lateral leg of the latter. 
     
     
         3 . The process, as set forth in  claim 2 , characterized in that the deformation of the upper closure hook and upper retention hook is obtained by applying an inward upward radial force, in opposition to the application of an outward radial force against the peripheral upper skirt and the upper end portion of the peripheral lateral wall, in order to simultaneously form the retention rib and the retention groove. 
     
     
         4 . The process, as set forth in  claim 2 , characterized in that the outer lateral leg and the outer lateral portion of the upper retention hook and of the upper closure hook respectively, are substantially rectilinear and inclined downwardly and radially inwardly. 
     
     
         5 . The process, as set forth in  claim 2 , characterized in that the inner lateral leg and the inner lateral portion of the upper retention hook and of the upper closure hook, respectively, are substantially rectilinear and slightly inclined upwardly and radially outwardly. 
     
     
         6 . The process, as set forth in  claim 2 , characterized in that the elastic sealing element has a portion of its extension penetrating and being compressed between the inner lateral leg and the inner lateral portion of the upper retention hook and the upper closure hook, respectively. 
     
     
         7 . The process, as set forth in  claim 2 , characterized in that the retention rib and the retention groove are formed by deforming the metal sheet of the respective parts and present a cross section with the approximate form of a rounded V, in a convex arc and a concave arc, respectively.