Pressed sheet-metal lid

Abstract: A pressed sheet-metal lid (10) comprises a peripheral band consisting of a groove (11) containing in its bottom an annular gasket (12) to receive and seal the mouth-piece of a container. Of the two walls of the groove (11) of adherence to the wall of the container the innermost one has drawn parts (14). In this manner when stacking several lids (10) they do not stick together. The outermost wall of the groove (11) can include tongues (13) bendable for clamping the lid to the edge of the container. As an alternative the outermost wall of the groove (11) can terminate with a thickened edge for fastening to the container by means of a compression band.

Description: Sheet-metal lids for sealed closing of containers such as drums or cans which comprise a peripheral groove to receive the upper edge of the container with the interposition of a sealing gasket are known. Said lids comprise also a discontinuous peripheral edge identifying a plurality of tongues for clamping to the edge of the container, or a continuous edge for fastening to the container by means of circumferential straps for radial and axial compression. To assure the necessary side seal of the container, the above mentioned peripheral groove must be relatively deep. This involves a considerable problem upon stacking of the lids during their production, storage and application to the containers. Indeed, the lids being pressed of relatively thin sheet metal, it happens that upon stacking they jam together, each groove receiving the back of the groove of the following lid in the pile. This makes it very difficult to automatically position the lids. In the known art it has been proposed to produce laterally and for the entire height of the groove, at regular intervals along the circumference of the lid, reliefs directed outward to prevent penetration in the groove of an overlying lid. Said reliefs, being pressed from the sheet metal, reduce the side surface of the groove which enters in contact with the side wall of the drum near the edge. To seek to reduce this shortcoming the number of reliefs is necessarily reduced to at most 5 or 6 for the entire circumference of the lid, thus reducing proportionately the effectiveness thereof in preventing jamming, also due to the elasticity of the edges of the groove resulting from the thinness of the sheet metal, not obviated by the lack of appropriate ribbing, and weakening the clamping of the lid on the mouthpiece of the container. In an attempt to prevent jamming between lids, the known art results in reduced quality of the fastening between the lid and the container because of the discontinuous nature of the contact surfaces caused by the reliefs or because of the elasticity of the part of the lid in contact with the side walls of the container. An example of said known art can be found in WO-A-8911423. The general object of the present invention is to obviate the above mentioned shortcomings and provide a pressed sheet-metal lid for closing containers as mentioned above and which would avoid the problem of jamming of several stacked lids and at the same time be sufficiently stiff. In view of said object it has been tought to provide in accordance with the invention a pressed sheet-metal lid as disclosed in Claim 1. To further clarify the explanation of the innovative principles of the present invention and its advantages in comparison with the known art there are described below with the aid of the annexed drawings possible embodiments as non limiting examples applying said principles. In the figures : FIG. 1 shows a bottom partial plan view of a lid provided in accordance with the invention, FIG. 2 shows a partial cross-section view along a radius of two lids such as the one shown in FIG. 1 stacked, FIG. 3 shows a partial cross-section view along a radius of a lid as in FIG. 1 clamped on the mouthpiece of a complementary container, and FIG. 4 shows a partial cross-section view along a radius of a variant of the lid as in FIG. 1, fastened with a band on the mouthpiece of a complementary container. With reference to the figures a lid 10 in accordance with the invention is shown schematically in figures 1 and 2. Specifically in FIG. 1 is shown a circular segment representing one fourth of the lid, the rest obviously being symmetrical. Along the periphery of the lid 10 is pressed a groove 11 containing in its bottom an annular gasket 12, the outermost wall of the groove terminating in a plurality of tongues 13 with their free ends curled. At regular intervals along the radially innermost wall of the groove 11 are drawn parts 14 directed toward the centre of the lid and hence projecting on the face opposite the groove 11. Said drawn parts 14 extend from the edge 16 of the groove 11 to a position intermediate between the edge and the bottom of said groove so as to identify a supporting surface 17 and at the same time leave available a side surface zone 15 continuing around the entire circumference of the lid. The walls of the drawn parts are virtually normal to the plane of extension of the lid. As shown in FIG. 2, when on a lid 10 is stacked an identical lid 10' (the prime suffix being used to indicate identical elements with identical numbers for the two lids 10 and 10') the supporting surfaces 17 of a lid enter in contact with the edge 16' of the other lid. Under these conditions the dimensions of the drawn parts 14 and the groove 11 are such that the projection identified by the groove 11 of the lower lid does not engage in the groove 11' of the upper lid, also because of the flaring form of the groove. FIG. 3 shows the described lid clamped to the mouthpiece of a drum 18. As may be seen in said figure the groove 11 receives the curled edge 19 of the drum 18, which compresses the seal and thus assures sealing. At the same time the tongues 13 are folded in such a manner as to close the groove 11 around the edge 19. The wall of the drum near the edge 19 is thus clamped between the circumferentially continuous wall 15 (of relatively ample height) and the bent back tongues, thus assuring good closing. The continuous wall 15 also constitutes a guide surface for fitting of the lid on the mouthpiece of the drum. FIG. 4 shows a variant embodiment of the lid described and indicated therein by reference number 10'' which permits fastening with a radially and axially compressed band 21 by reduction of the diameter by the known art. In said variant embodiment the outer edge of the receiving groove for the edge of the mouthpiece of the drum has no tongues and terminates with a circumferentially continuous curled edge 20 to be clamped by the band 21 against the edge 19. As may be seen in the figure the continuous surface 15'' (analogous to the surface 15 of a lid 10) constitutes an ample and continuous contact surface with the internal wall of the drum, thus assuring the quality of the closing. The characteristic of not jamming between lids is maintained unvaried by means of drawn parts 14'' with upper rabbet surfaces 17'', which are analogous to the drawn parts 17. In both embodiments the drawn parts 14, 14'' arranged along the circumference at regular intervals afford substantial stiffening of the lid and contribute to adherence by forcing the surfaces 15, 15'' against the inner wall of the drum. Said stiffening in turn contributes to the possibility of providing a relatively deep groove with ample lateral adherence surfaces between the lid and the drum. Although the invention has been described in conjunction with a specific embodiment it is evident that many alternatives and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, the invention is intended to embrace all of the alternatives and variations that fall within the scope of the claims. It is thus understood, for example, that the proportions of the parts as shown in the figures are to be considered indicative and may vary depending on the thickness of the materials and the characteristics of the desired seal, as the method of fastening between the container and the lid may vary.

Claims: Pressed sheet-metal lid (10) comprising a discoidal portion and a virtually cylindrical peripheral band (15) with an edge identifying a circumferential groove (11) to receive the edge (19) of the mouthpiece of a cylindrical container (18) for sealed closing thereof characterized in that said band (15) comprises a first and a second circumferential zone of adherence to the inner side wall of the container (18), the first zone bordering on the second zone along a circumferential line, there being provided in the second circumferential zone adjacent to the discoidal portion drawn parts (14) spaced along the circumference in order to locate between the first and second zone in proximity of said circumferential line a surface (17) radially projecting towards the centre of the lid, between the drawn parts (17) the second circumferential zone laying on the same plane of the first circumferential zone. Lid (10) in accordance with claim 1 characterized in that on the bottom of said groove (11) is arranged a sealing gasket (12) for the edge (19) of the mouthpiece of the container (18). Lid (10) in accordance with claim 1 characterized in that the wall of the groove (11) toward the outside of the lid comprises a plurality of tongues (13) directed in a virtually normal manner to the plane of the lid and bendable for clamping to the edge (19) of the mouthpiece of the container (18). Lid (10) in accordance with claim 1 characterized in that the wall of the groove (11) toward the outside of the lid (10) comprises a continuous edge (20) for fastening to the edge of a container by means of a circumferential and axial compression band (21) for reduction of the diameter of the band (21).

Inventors: PAGANI DOMENICO, PAGANI LUIGI, PAGANI, DOMENICO, PAGANI, LUIGI
Applicants: LIMEA FISMA SPA, LIMEA-FISMA S.P.A.
Application year: 1990
Main classification: B65D43
IPC codes: B65D43, B65D45