Patent Publication Number: US-5289938-A

Title: Rim structure for metal container

Description:
FIELD OF THE INVENTION 
     The present invention relates to a rim structure for defining the mouth or opening of a metal container. 
     BACKGROUND OF THE INVENTION 
     From U.S. Pat. No. 4,865,212 there is disclosed a rim structure for a metal container having a rim that is an integral part of the container cylindrical sidewall. One of the drawbacks of this known rim is that the rim has not enough rigidity in the container mouth, and any accidental fall or dropping of a full container may cause the lid to be opened because the mouth may be detrimentally strained. 
     With the rim structure of the present invention, more compact rigidity in the container mouth is obtained which is only comparable to that achieved by conventional rims which are separately produced and which must then be separately secured to the edge of the container sidewall using a special operation. However, the rim structure of this invention preserves the low-cost advantages provided when the rim is incorporated to the container in a single operation. 
     Additionally, with the rim structure of the present invention, due to the particular rim configuration provided, a more specific lid airtight seal and a better lid holding in its sealing position is obtained so as to better resist blows or drops which might tend to cause accidental opening. 
     Lastly, with the improved rim structure all of the rim outside visible portions have the same finished appearance as that of the container sidewall, thereby giving the rim an improved aesthetic appearance relative to most known metal containers. Most known metal containers are generally provided with an appearance or rim color quite different to that of the container external walls due to these components being separately made. 
     In the mouth of the container of this invention, rigidity is provided by specific edge bending of the container sidewall making up the rim and shaped by an outwardly projecting length with a tilt of about 45°, this length being radially inwardly folded over onto itself and then vertically upwardly raised and radially outwardly folded to define a generally triangle-shaped cross section. The top free end of the triangle is extended according to a vertically upwardly short length, being afterwards inwardly folded over onto itself so that a rounded edge can be shaped. 
     This peculiar configuration determines an internal step close to the mouth, its top portion being flexible or resilient, and this resiliency being provided by the free outwardly deflection of the vertically internal length determining said step. This resiliency allows an annular projection, as provided on the container lid outside sidewall, to be snap-fitted through the step length, with the projection snapping under the stepping edge and being then fixed to create a highly resistant snap-fit against accidental opening. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary cross-sectional view through the rim of a container according to the present invention. 
     FIG. 2 is a fragmentary cross-sectional view of the lid of the container. 
     FIG. 3 is a similar view showing the lid in a sealing position on the container. 
     FIG. 4 is an enlarged, fragmentary cross-sectional view through the rim. 
    
    
     DETAILED DESCRIPTION 
     The drawings show a cylindrical metal container 1 having a cylindrical sidewall 2 and defining an opening or mouth 3 at one end thereof, which opening is surrounded by an annular rim 4 which is designed to receive the annular flange of a removable lid or cover 5 provided with an annular projection 6 to create a hermetic seal. 
     The V-shaped configuration of the rim 4 allowed its length 7 to be outwardly radially deflected and a smooth insertion, however snap-fitted, of the rib or projection of the lid 5 and its pressurized engagement at the stepping 8. 
     The rim structure 4 projects upwardly from and is integrally joined to the upper end of the cylindrical sidewall 2 at plane 10, and includes an annular wall part 11 which diverges or flares outwardly, such as at an angle of about 45°, as it projects upwardly from the upper end of the cylindrical sidewall 2. This diverging annular wall part 11 resembles a truncated conical configuration. The diverging wall part 11, at its upper end, is folded over radially inwardly onto itself to form a rounded annular outer top flange 12 which has an outwardly rounded cross section, and which then extends downwardly inside the exterior wall part 11 so as to define a further inclined annular flange 13 which is generally straight and which converges inwardly as it projects axially downwardly in closely adjacent and approximately parallel relationship with the outer wall part 11. 
     The inclined flange 13 projects axially downwardly and radially inwardly so that the lower end of this flange is positioned in a horizontal plane which is adjacent but spaced slightly upwardly from the location or plane 10 where the exterior wall part 11 merges into the adjacent upper end portion of the cylindrical sidewall 2. At its lower end, the flange 13 is folded over radially inwardly onto itself to define a generally V-shaped annular fold 14 which is tightly rounded at the bottom and which opens upwardly. 
     The fold 14 and its slight axial upward spacing from the location or plane 10 results in creation of the shallow annular step or groove 8 disposed in surrounding relationship to the rim adjacent the upper end of the cylindrical sidewall 2, which groove 8 opens radially inwardly of the rim. 
     The fold 14 joins to an annular vertical flange 15 which projects axially upwardly so as to be substantially straight and substantially parallel with the longitudinal (i.e., vertical) axis of the container. This annular flange 15 defines the mouth or opening 3 of the container. The inner surface of this flange 15 is substantially coaxially aligned with the inner surface of the upper and adjacent part of the cylindrical sidewall 2, and has a diameter which approximately equals the inner diameter of the container as defined by the adjacent upper portion of the cylindrical sidewall 2. 
     The vertical flange 15, at its top or axially outer end, is folded over radially outwardly by a fold or bend 17 which is about a 90° bend and joins to an annular top flange 18 which projects radially outwardly from the bend 17, with this top flange 18 projecting outwardly adjacent but generally axially over the fold 12. The radially outer edge of top flange 18 in turn is folded upwardly and radially over onto itself to form a rounded annular outer top flange 19 of generally rounded cross section, which top flange 19 terminates in a free edge. This top flange 19 is disposed closely adjacent and is generally disposed axially directly over the fold 12. 
     As described above, and as illustrated by FIG. 4, the flanges or wall parts 13 and 15 and their connection by the fold 14 defines a generally V-shaped arrangement which, in conjunction with the projection of the top flange 18 outwardly over the top of the fold 12, enables the vertical flange or wall 15 to be resiliently deflected radially outwardly so as to resiliently accommodate the insertion or removal of the lid. 
     As described above, and as shown in the drawings, the entire rim arrangement 4 is formed integrally with the thin sheetlike metal material defining the cylindrical sidewall 2 so that the rim arrangement 4 and sidewall 2 are of an integral one-piece structure all formed from thin sheetlike material of substantially uniform thickness. 
     As to the lid 5, it includes a central generally flat cover portion 20 having the annular mounting flange 9 extending circumferentially therearound. This flange 9, in the illustrated embodiment, is of a generally upwardly-opening U-shaped cross section including an inner annular wall 21 which projects downwardly from the central cover 20. This inner annular wall 21 at its lower end is bent outwardly to define an annular bottom wall 22, and the bottom wall 22 at its radially outer edge is bent upwardly so as to define the upwardly projecting outer annular wall 23. This latter wall 23 projects upwardly in cantilevered relation and has the upper edge thereof folded outwardly and downwardly to form a rounded fold 24 at its upper and outer free edge. The outer annular wall 23 of the lid flange also has the bead-like annular projection 6 formed therein, which projection 6 projects radially outwardly from wall 23 and extends annularly thereof. 
     With the arrangement of the present invention as described above, the flange 9 on the lid 5 is inserted into the mouth 3 defined by the rim structure 4. During this insertion, the sealing projection 6 on the lid flange cams against the annular flange wall 15 of the rim and causes radially outward resilient reflection until the sealing projections 6 snaps into the annular groove 8, whereupon the rim structure resilient returns to its original position and creates a resilient but releasable holding of the lid on the container. The snug engagement of the lid flange within the mouth opening defined by the rim structure, and the snug engagement of the sealing projection 6 within the groove 16, define a generally hermetically sealed engagement between the lid and container, and provide an airtight seal and a secure holding of the lid so as to better resist accidental dislodgement of the lid due to dropping of the container and the like. At the same time, the rim structure of the container is sturdy and provides a desired compactness which facilitates effective sealing of the lid. 
     Also, the manner in which the rim is formed on the container is such that the finished appearance of the container remains smoothly and ecstatically pleasing without requiring any additional treatments so as to equalize or disguise the rim structure, whereby the container has a better overall appearance when such is deemed necessary or desirable. 
     Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.