US2041912A

US2041912A - Closure cap for receptacles and method of making the same

Info

Publication number: US2041912A
Application number: US723645A
Authority: US
Inventors: Edward H Fabrice
Original assignee: GUARDIAN SAFETY SEAL Co
Current assignee: GUARDIAN SAFETY SEAL Co
Priority date: 1934-05-03
Filing date: 1934-05-03
Publication date: 1936-05-26
Anticipated expiration: 1953-05-26

Description

9 E. H. FABRIC-E aww CLOSURE CAP FOR RECEPTACLES AND METHOD OF MAKING THE SAME Filed ay 3, 1954 atented May 26, 1936 UNITED STATES PATENT oFFicE CLOSURE CAP FOR RECEPTACLES AND METHOD OF MAKING THE SAME Application May 3, 1934, Serial No. 723,645

-5 Claims. (01. 215- 46) The invention relates particularly to that type of receptacle closure cap made of sheet-metal and which includes, as an integral part thereof, a severable portion or band bordered by one or more weakened lines or scorings.

The main object of the present invention is to effect the weakening of the metal along a line or lines bordering the severable portion of the cap, in such a manner as to avoid the production of an exposed rough, burred edge on the cap along the line of severance during the-severing operation and which, ordinarily, tends to cut or injure the fingers of the operator in the manipulation of the crown portion of the cap for unsealing and rescaling the receptacle.

A further object of the invention is to provide a method of effecting weakening of the metal along a. line or lines, as aforesaid, to render one portion of the device severable from'the other, in such manner as to effect an appreciable thickening of the metal of the cap at each side of each weakening line, so as to increase the stiffness of the edge portion of the retained part and also to cause the line of fracture of the metal to be rendered more brittle than the balance of the material of the cap and cause a breaking of metal along said severance line or lines, rather than a tearing away by tension of a-portion or part of the metal of the cap which results in the production of burred edges.

A suitable embodiment of the invention with respect to product and method, is illustrated in the accompanying drawing, wherein:-

Fig. 1 is a view in side elevation of the discharge end portion of a bottle neck, or the like, equipped with'a closure cap constructed in accordance with the invention.

Fig. 2 is a view similar to Fig. 1 showing a slight modification of construction of the cap.

Fig. 3 and Fig. 4 are fragmentary sectional views on an enlarged scale, illustrating the method of the present invention and also details of construction of the closure cap, said Figs. 3' and 4: being fragmentary, vertical longitudinal sections on the lines 3-3 of Fig. 1 and t-t of Fig. 2, re-

spectively.

Fig. 5 is a fragmentary detail sectional view similar to Fig. 3, showing the condition of the cap at opposite sides of a fracture thereof, after the severable portion of the cap has been removed therefrom.

Fig. '6 is a view similar to Fig. 5 showing an internalinitial weakening groove in the skirt portion of the capi,

The type of closure cap to which the present invention relates is well known in the art and, in the instance illustrated, is shown as comprising an inverted sheet-metal cup consisting of a crown portion i which is equipped with screw threads,

a skirt portion 2, the lower edge portion 3 of which end in a digitally engageable tongue I which is severed from the body of the cap along a top incision 3 which is flush with the upper weakening depression 6 and which is continued around the extremity of the tongue I and borders the latter, said incision 8 meeting the lower annular depression 6 at both ends of the tongue I.

Below the screw threads of the crown portion l of, the cap and bordering the upper edge of the severable strip 5 thereof, is an annular bead 9 in the crown of which the upper weakening depression is made, and the upper portion of said bead 9 constituting a flaring mouth for the crown portion I of the cap after removal of the strip 5 from the latter.

The structure shown in Fig. 2 is identical with that of Fig. 1, except that. in addition to the bead 9 of the cap of Fig. 1, a second bead ill is provided, in which the lower weakening depression v6 is-made,-as in the case of the bead 9.

Heretofore, it has been customary in the art to effect weakening of sheet-metal for the purpose of efiecting casy severance thereof, along a predetermined. line or lines, by cutting partly through the material along said lines by means 3 of a sharp-edged knife-like roller, cooperating with a suitable mandrel or other support, for the face of the metal opposite that in which the cut or cuts are to be made.

It has been found in practice that this cutting partly through the sheet-metal causes the parts severed along the line or lines of the cuts, to present rough, burred edges which are very undesirable'. Furthermore, the tensile strength of sheet-metal is apt to vary at different points and the sharp knife edges of. the cutting tool are apt to become dulled quickly at points along the cutting edge, withthe result that the cuts effected are not uniform and thus a severable strip, such as the strip 5 illustrated in Figsi and 2, is apt to be torn laterally during the operation of attempting to sever the whole strip from the cap. The dulling of the cutting edge'used to efiecting scoring occurs quite rapidly and necessitates ire To overcome the objections to rough, sharp edges, and the inequalities of depth of the weakening lines referred to hereinabove, my invention comprehends the weakening of the sheet,- metal along predetermined lines of severance by effecting compression of the metal along said lines by the formation of a substantially V-shaped groove therein having a round bottom wall and more widely diverging side walls than are produced by a sharp-edged cutting tool.

As shown in Figs. 4 and 5, the grooves 6 are produced by the cooperation of a suitable mandrel with a roller I I having one or more substantially V-shaped annular ribs I2, the side faces of. which converge toward the rounded outer edge I3 thereof, at an angle of approximately ninety degrees to each other and forty-five degrees to the circumferential face of the roller II. The mandrel used for cooperation with the roller I I is omitted from illustration as not requisite to an understanding of the invention by persons skilled in the art.

The roller is applied to the cap with sufficient force to form the grooves 6 so that the thickness of the metal at the bottom of the grooves 6 and between the latter and the opposite face of the metal, is reduced to fifty percent, more or less, of

the normal thickness of. the sheet-metal. A roller is preferable to any other device for forming the groove or grooves 6, because it forms the same progressively.

The metal displaced by combined action of roller and mandrel is displaced to the sides of the groove and effects a thickening of the metal adjoining the groove, so that the portions of the metal, and especially the opposed edges of the crown and skirt members of the cap herein illus; trated, are stiffened to a sufficient extent to prevent their distortion during the operation of etfecting severance ofthe strip 5.

The pressure applied by the roller I I in cooperation with a mandrel also effects a hardening of the metal along the bottom of the groove to render the same appreciably more brittle than the balance of the cap and this causes a break- I ing of. the metal along the bottom of the groove of the strip has been removed.

This operation tends, of course, to cause the upper edge of the skirt portion bordered by the grooves 6 to become flared outwardly and likewisetends to cause upper portion of the bead 9 to become flared more fully than is shown in Fig. l, and in the case of weakening lines or scorings produced by cutting, as distinguished from compression of the metal along these lines, such flar-' ing occurs and causes the closure caps to present edge dangerous to the fingers of. the operator. In the instance of the present structure, hereinabove described, the severance takes place more easily, more uniformly and without effecting distortion of the portions of the cap bordering the severable strip 5.

It will be notedfas shown in Figs. 4 and 5, the displacement of metal in forming the grooves 6 produces the rounded or upset edges I l bordering said grooves.

A very appreciable advantage of the invention resides also in the fact that the groove-forming element of the roller wears away very slowly and 5 permits uninterrupted operation for many times the life of the cutting edge of a groove-cutting tool.

The formation of the grooves 6 progressively is also advantageous in that it effects a greater 10 degree of upsetting of. the edges of the crown and skirt portions of the cap and less stretching of the metal thanis true of the use of dies operating over a substantial length of groove at each operation, as in the case of receptacle 010- 15 sures wherein grooves are formed in flat metal faces.

It will be noted that the files of the rollers employed for forming the grooves 6 are such that the displaced metal is rolled to a somewhat flat curvature in cross-section, the portions of the profiles of the rollers which meet in the curved outer edge of the groove-forming ribs I2 are of arcuate contour and effect shaping of the ridges I4 border the grooves 6. r

As shown in Fig. 6, the weakening groove I5 may be formed in the opposite face of the metal from that wherein the companion groove 8 is formed and this arrangement has been found to be preferable in some instances.

The drawing illustrates the invention by greatly exaggerating the thickness of the sheet metal. In the thin sheet-metal caps, the ridges II are of somewhat microscopic dimensions and are appreciable to the touch rather than. the eye. The weakening grooves 6 however, are so much more pronounced than the weakening cuts or scorings heretofore made to define the severable strip of the cap as to be far more visible and tangibly appreciable to the touch.

Caps of the type herein illustrated are made of thin sheet-aluminum or aluminum alloy and the advantages of the present invention are distinctly tangibly appreciable over the results of the groove cutting operations heretofore practised.

The invention may be applied to any type or style of structure wherein sheet-metal is used and is weakened along a line or lines for effecting severance of one part of the structure from another thereof.

I claim as my invention:

1. A sheet metal closure cap for receptacles having a skirt portion equipped with an annular metal thinning and weakening depression in one face only thereof, said depression presenting a 55 rounded bottom wall, and a pair of annular ribs bordering said depression and constituting thickened portions of the metal resulting from displacement of metal from the said depression.

2. A sheet metal closure cap for receptacleshaving a skirt portion equipped with a pair of annular ribs projecting from one face thereof and constituting metal thickening formations, said ribs bordering an annular groove in said face of said skirt portion extending to a depth sufficient 65 to thin and weaken the metal of said skirt portion to render the latter readily fracturable along-said groove, the face of the skirt portion opposed to said ribs and groove being undistorted. 1

3. A sheet metal article such as a closure cap for receptacles, provided in one face only of its skirt portion with an annular metal thinning and weakening groove, having a rounded contour void of sharp corners, in cross-section, and. a pair of metal thickening ridges bordering. said groove and having a rounded contour in cross-section merging into the said contour of the groove, said ridges being composed of metal displaced by forming said groove.

. therewith and projecting from the face of the said skirt portion containing said grooves, the other 5. A sheet metal article such as a, closure cap for receptacles equipped in its skirt portion with a pair oi? parallel annular metal weakening depressions in one face only thereof, and-a pair of i annular ridges bordering each of the respective grooves and constituting metal thickening format-- tions resultingfrom displacement of metal in eiTecting said depressions, the other face of said skirt portion being devoid of distortions resulting from the production of said depressions and ridges.

EDWARD H. FABRICE.

face of said skirt portion remaining undistorted.