US2168565A - Closure cap and method of making - Google Patents

Description

Aug 8, 1939. J. c. GIBBS 8 6 CLOSURE CAP AND METHOD OF MAKING Filed March 17, 1936 INVENTOR (70% a (110w i M ATTORNEY Patented Aug. 8,,l939- UNITED I STATES 1 ATENT OFFICE I v onosrma can 13320 01 John 0. Gibbs, Brooklyn, N. Y., assignor to Anchor Cap & Closure Corporation, Long Island City, N. Y., a corporation of New York Application March 11, 1936, Serial No. 69,286 a 3 Claims. (or. 113-121) The present invention relates to the production of closure caps and more particularly to screw closure caps and an improved method of making such caps.

Packers and bottlers are greatly'interested in the appearance of their packages, which may be impaired or enhanced by the closure cap used for sealing the packages. Packages, are, for the most, part, purchased by housewives, who are guided in their purchases to a considerable extent by the attractiveness orbeauty of the package. Various attempts have been made to obtaincaps which are attractive in appearance. Closure caps molded of phenolic condensation products and other synthetic resins or molding compounds have become quite popular due to their attractiveness. This popularity was attained i-nspite of the fact that the closures do not form a better seal, are more expensive, and are subject to breakage because of their frangible nature. Various attempts have been made to make metal caps which would have the attractiveness of molded capswithout the disadvantages. One solution was to utilize two nested metal caps, the inner cap serving as the sealing'cap and the outercap as a cover cap or shell to conceal the screw threads or container engaging means and other irregularities of the inner cap. Such caps are subject .to the objection of increased cost, due to the extra closure or cover cap, and due to the extra operations necessary in manufacturing and assembling the caps. In addition, occasionally the two closures rotate with respect toeach other, which prevents the cap from being unscrewed from a container and properly applied to form a seal. Plain skirted caps have also been made by turning the edge of the cap inwardly and forming lugs or short thread projections from the inturned edge or bead. The method of manufacturing such caps increases the cost. In addition, such caps cannot be applied to a. container provided with a continuous thread finish. The latter finish is more. prevalent and is frequently demanded by the packer or bottler for certain types of packages.

The present invention aims to provide an inexpensive closure cap adapted to fit on a continuousthread finish having the advantages of molded and double shell caps without having the disadvantages of either. The invention aims further to provide an inexpensive practical method of making the caps, which decreases their cost and improves their appearance by eliminating with concealed threads on the interior thereof.

is the first step of forming the cap;

Another object of the invention'is to provide an improved method for forming thread engaging means on the inside of the cap wlthout'reforining the exterior thereof.

Another object of the invention is to reduce the cost of manufacturing metal screw caps having a plain skirt.

Another object of the invention is to provide a practical method of making screw caps having a concealed thread. Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be. described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred mbodim'entof the invention has been chosen for purposes of illustration and de-' scription and is shown in the. accompanying drawing, forming a .part of the specification, wherein- Fig. 1 is a sectional view illustrating a blank after it is'stamped from a sheet of metal, which Fig. .2 is a sectional view illustrating the sec ond step of a method of forming the cap;

Fig. 3 is a sectional view illustrating the third step in forming the cap;

Fig. 4 is a perspective view illustrating a com pleted 7 cap;

Fig-5 is a fragmentary side elevational 'view, partly in section, of a glass container with the cap shown in Fig. 4 sealed thereon:

Fig. 6 is'a sectional view illustrating the second step in another method of forming a cap;

Fig. 'I is a fragmentary sectional view of a. cap finished from the blank shown in Fig. 6;

Fig. 8 is a fragmentary sectional view of a finished cap, the shape of the blank after the second step of manufacture being indicated in dotted lines; r r Fig. 9 a fragmentary sectional view of a cap illustrating anotherembodiment of the invention, the shape of the blank after the second step of manufacture being indicated in dotted lines; and Fig. 10 is a fragmentary sectional view ,of acap illustrating still another embodiment of the invention, the shape of the blank after the second step being shown in dotted lines.

Referring again tothe drawing, and more particularly to Figs. 4 and 5 thereof, there is shown a closure cap made of sheet metal such as tinplate, aluminum or the like, having a cover portion I and a depending skirt or flange 2. The lower edge of the skirt has a slit or slot 5 therein and is turned inwardly and upwardly, as shown at 4.

The slot 5 is provided to facilitate the formation of the skirt of .the cap and particularly i the folding of the lower edge thereof. A screw the purchaser or manufacturer.

thread 6 is formed in the inturned part 4 of the skirt by a groove 1 having a convex surface 8 facing inwardly toward the center of the cap.

It will be understood, of course, that the thread sufficient to be visible from the exterior of the cap. In this way, the raw edge formed by cutting the slot is concealed within the skirt of the cap and the lower edge of the skirt of the finished cap is smooth andunmarked.

In Fig. 5 the cap illustrated in Fig. 4 is shown sealed to acontainer having a continuous thread 9. The thread 6 of the cap fits under the thread 9 of the container to hold the cap on the container and to compress a sealing liner between the cover of the cap and the rim of the container.

The liner is usually assembled with the cap and may be'made of cardboard, cork, rubber, or the various other types of sealing material. It may also be in the form of a ring of similar material, if desired, the function thereof being to form a liquid-tight or hermetic seal. The cap is screwed on the container in the same manner as other types of screw caps. The exterior of the cap, however, is preferably plain, with the screw thread 6 invisible, as shown. It will be understood, however, that the cover of the cap or skirt may be shaped to conform to the taste of Such shaping of the skirt may be independent of and free from the deformation necessaryin the formation of the thread.

A method of forming the closure described above is illustrated in Figs. 1 to 4. The blank shown in Fig. 1 may be stamped from a sheet of decorated metal and the slot may be formed simultaneously therein by the same operation.

The length of the skirt may be uniform throughout the circumference or as in the embodiment described hereinafter it may be of a varying length. In'the second step, the lower portion of the skirt is turned upwardly and inwardly into the cap to form a hollow head, as shown in Fig. 2. This may be accomplished in any suitable manner, for example, by a curling or a rolling operation, but the former is preferred. If desired, the lower edge of the skirt may be bent inwardly slightly prior to the second operation as shown in dotted lines in Fig. 1 to facilitate the rolling or curling operation. Thereafter, in the third step, as shown in Fig. 3, the bottom portion 4 of the skirt 2 forming the bead is reformed to provide the groove 1. The die members in Fig. 3 are shown applied to a cap with the cap in its upright position. In normal manufacturing operations, the cap would preferably be in inverted or edgewise position and the position of the dies changed accordingly. Preferably, the third step is performed by placing the cap blank into a cup-shaped die A conforming to the outer contour of the cap and engaging die B having a helical portion H thereon adapted to push portions of the bead upwardly and outwardly against the skirt to reform the bead into a thread. While to support the upper convex edge 8 of the bead.- The anvil C preferably is in the form of an expandibie chuck comprising several segments adapted to be expanded against the inner walls of the skirt and to be contracted for inserting and withdrawing the chuck past the thread portions. The lower edge of the anvil chuck C is provided with helical portions l2 corresponding to the helical thread forming portions of thedie member B. The helical portions'of the dies B and C determine the inclination of the thread and the position of the thread with respect to the lower edge of the skirt. The die B preferably has a groove I3 therein adapted to receive the lower edge of the skirt to maintain the shape of the lower edge and press the lower portions of the upwardly folded bead against the inner side of the skirt. In this manner both the outer skirt portion andthe inturned part 4 are rigidly supported and reinforced and the groove l is positioned in the interior of .the skirt to provide the thread 6.

The slit 5 plays an important function in the method and in the resulting cap in that it permits the inturned portion 4 to be folded inwardly and upwardly by a bending or folding operation. Without the slit 5, it would be necessary for the lower edge of the cap to be compressed during the reforming operation. During such compression there is a tendency for the metal to wrinkle and the operation is otherwise difiicult and expensive. The present closure may be formed by a simple bending operation which minimizes the strain on the metal and which does not impair the lacquer. The, operation is sufficiently simple so that the groove or thread, if desired, may be formed in the blank before the metal is turned inwardly, as illustrated in Figs. 6 to 10. While the die members A and B and the chuck C are illustrated diagrammatically, it will beunderstood that they may be in any desired form and are adapted to be associated with any desired automatic cap fabricating machine.

The cap shown in Fig. '7 is similar to the one shown in Fig. 4 and may be made by a similar method. The helix angle of the thread 6 is ob tained by making the skirt 'of the blankbf uneven length, preferably the bottom of the skirt being in the form of a spiral conforming to the helix angle of the thread desired. A groove 1 is then formed, as shown in Fig. 6 at the bottom of the skirt which has a spiral formation so that the convex side of the groove, when turnedinto the cap as shown in Fig. 7 will form a thread 6' of the proper helix angle. Preferably, the formation of the groove 1' is uniform throughout its length. In Fig. 'I the lower edge of the skirt is shown folded into the cap so that the thread extends radially inwardly from'the inner side of the skirt. This operation may be accomplished by a suitable curling die B while a chuck C is utilized tosupport the upper edge of the thread.

thread within prescribed tolerances, but may be omitted. It will be understood also that the cap shown in Fig. 7 may be made by the method illustrated inFigs. 1, 2 and 3.

The cap shown in Fig." 8 may be formed from a blank of uniform length and the groove I may b rolled into the blank as shown in dotted lines in Fig. 8 before the edge is folded inwardly and upwardly. The groove, at the time of the formation, has the proper helix angle to form a suitable thread 6' when it is turned in.

I perfect sealing results and has suflicient-resil- The cap sh own in Fig.9 is preferably formed from a blank having a skirt cut at a helix angle corresponding substantially to the helix angle of the thread on the container, and the lower edge of the skirt of the blank is rolled outwardly and upwardly into "a wire edge It, as shown in dotted lines in Fig. 9'. of the skirt is folded inwardly as shown at l5. with the wire edge It forming-the thread for the cap. With the aid of the notch or slit in the skirt of the cap, the lower edge of the skirt having the wire edge formed on it may be folded into the interior of the skirt without difllculty. It will be understood that the plurality of notches similar to the notch 5 may be utilized, if desired.

In Fig. the formation of the cap is similar to that in Fig. 9 except that the lower edge of the blank is rolled inwardly into abead IS on a I bead is a more diflicult operation than rollinghelix angle and thereafter the entire bottom part I of the skirt is folded upwardly into the cap to provide a thread. The rolling inwardly of the outwardly, but it may be advantageous in certain cases. In the formation of the caps of Figs.- 9 and 10, the skirt of the blank may, if desired, be of uniform length and the helix angle may be obtained by rolling the rolled edge-on the blank more at one point than at another to obtain the helix angle and thereafter turning the bottom of the skirt inwardly and upwardly to complete the cap as described above. i

. It will be understood, of course, that'in the formation of the present cap it may be desirable, in some instances, to perform certain of the operations after the loweredge of the metal has been folded inwardly. For example, it may be desirable to roll or otherwise further compress the bottom edge of the skirt so that the infold'ed bottom portion 4 will be in closer contact with. the skirt 2.,

In the manufacture and sealing of metal 010- sure caps, the caps are made in a cap factory and the containers in a glass factory. Preferably, the liner I0 is assembled in the capby automatic machinery and shipped in assembled state. The packer. may dump the caps .into the hopper of an automatic machine,'which will apply them to the containers or he may screw the caps on the containers by hand. The housewife removes the cap manually by unscrewing it. The construction of the cap is such that a wide range of variations in the size of the glass container can be accommodated without the cap being difiicult to apply or remove. The formation of the thread gives greater resiliency and more holding power than is present in the ordinary types of screw caps. The thread by the skirt, eliminates relative movement between. it and the skirt and by being formed by metal turned inwardly and upwardly, provides a support for the liner l0 and prevents it from falling out of the cap.

It will be seen that the present invention pro-- Thereafter, the bottom being an integral part of iency and flexibility to accommodate the variations in the size of glass containers. The slot in the bottom of the skirt blank permits the metal to be folded inwardly without material strains on the metaLor marringthe lacquer or coating. The'slot also permits the/end of the container thread to pass .between the respective ends of the cap thread so that the cap thread may be screwed under the container thread. The cap has all the advantages in appearance of a molded or a double shell cap and eliminates the disadvantages of each. h

As various changes may be made in' the form, construction and arrangement of the parts herein without departing from the spiritvand scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and\ not in a limiting sense.

' 20 Having thus described my invention, I claim:

1. The method or making closure caps, which method comprises forming a blank having a 'cover portion and a depending skirt, slitting the .lower edge of the skirt, folding the lower portion of the skirt inwardly and upwardly to form a bead interrupted at one point by said slit, and compressing said head by means of two dies having opposed complementary helical surfaces designed to engage the bead, thereby to form a helical thread, the relative positions of the dies and the slit in the cap being such that the thread .in the cap begins and ends on the respective'sides of the slit. T

2. The method of making closure caps, which method comprises forming a blank having a cover portion and a depending skirt, slitting the lower edge of the skirt, folding the lower portion of the skirt inwardly and upwardly to form an inturned bead interrupted at one point by said slit and compressing said bead ing opposed complementary helical surfaces designed to engage the bead thereby to force certain portions of'the bead outwardly against the wall of the closure to form a helical thread from other portions thereof, the relative positions of the dies and the slit in the cap being such that the thread in the cap begins and ends on the respective sides of the slit.

- edge thereof, said inturned bead having one vertical slit therein concealed from view by the skirt of the cap when viewed from the exterior, the ,lower portion of said inturnedbead being flattened against the skirt of the cap throughout the circumference of the skirt to provide a continuous thread in the cap by afold of metal in the inturned bead, said fold being compressed to provide a helical thread adapted to engage a thread on the container which extends substantially entirel'y about the skirt of the cap, commencing at one side of said slit and terminating at the other side of said slit, thereby-facilitating entry of a container thread between-the ends of said cap thread at said slit, said thread having a substantially constant width and depth throughout its length.

JOHNC. GIBBS.

40 by means of two dies hav-

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