US2350312A - Can closure and method of making the same - Google Patents

Description

May' 30, 1944 r A. e. HATCH 2,350,312 7 CAN CLOSURE AND METHOD OF MAKING THE SAME I Filed Feb. 1o, 1945 2 Sheets-Sheet 1 May 30, 1944. I 'A. G. HATCH 2,350,312

CAN CLOSURE AND METHOD OF MAKING THE SAME Filed Feb. 10, 1943 2 Sheets-Sheet 2 Eg -5 a 1 J INVENTOR." I flzez'aizderdfiaztia W *MMJ wiiiorzae ys Patented May 30, 1944 THE SAM

Alexander Hatch, ltutland, Vt., assignor to ry Corporation, Rutland,

Fibre Can Machine Vt., a'corporation Application February 10, 1943, Serial No. 475,351

1 Claim. ('Cl. 229-55) The present invention relatesto closures for cans utilized for the packaging of motor oils and the like, and, more particularly, to top closures for fibre bodied containers intended for the purposes mentioned. The invention also relates to" the method of making the closures and applying the same to the can bodies.

It is recognized that closures forme of fibrous material for closing the bottoms of container bodies have been proposed which are generally "satisfactory, but' so far as I am aware, no satisfactory closure has been provided whichmay be used to cover and seal the top of the container after the same has been filled with a liquid.'

Many efiorts over a long period of years have been made in an endeavor to provide a satisfactory top closure which meets necessary requirements, but so far as the practical art is developed, no such closure, prior to the present invention, has been produced.

Therefore, an aim of the present invention is to provide an improved and novel closure having various features of novelty and advantage and which is peculiarly adapted for use for closing the top of the container after the container has been filled with a liquid or the like.

A further object of the invention is to provide very simple, economical, and effective closures which may be cheaply manufactured and sold as complete unitary structures and which may be very quickly and readily assembled on the can bodies and particularly on the tops of the can bodies after they have been filled with oils or'the like.

A further object of the invention is to provide a closure which is very strong and sturdy; which will withstand hard usage, and which is capable of effectively resisting blows and shocks exerted thereon when the can is roughly handled or dropped. In fact, a closure constructed in accord'ance with the present invention, when applied to a can body, is capable, although the closure comprises a body member of fibrous'material, of better withstanding shocks and blows than are metal closures such as are usually employed on containers of this sort.

.j 'A further aim of the invention is to provide a closure which will provide an eflective liquid-tight and leak-proof joint between the closure and the end of the can body to which the closure is applied. Further, th arrangement is such that the liquid contents of .the container cannot gain access to the end of th fibre can body, with the result that wicking is prevented, that is, the liquid cannot gain access to the raw edge of the can body and then permeate through the wall thereof. A still further object of the invention is to provide a closure of simplified construction and one which may be inexpensively manufactured, it being possible with my improved arrangement to make the closure out of inexpensive materials and to produce the closures at high rates of speed -so that they can be produced at a relatively low cost, the said closures so produced being in the form of self-contained units or structures which are ready for application to the can bodies and particularly to the'tops thereof after the. same have been'filled with oils or the like. 7

A further object of the invention is to provide animproved and simplified method formanufacturing my improved closures and applying the same to the ends of a can body and particularly the top thereof.

Other objects will be in. part obvious and in part pointed out more in detail hereinafter.

In the accompanying drawings: Figure 1 is a side elevational view of one embodiment of my improved closure with portions thereof in central transverse section;

- Fig. 2 is a view similar to Fig. 1 but showing the improved closure thereof assembled on a can 'proved closure comprises a body member to formed of fibrous material, such as. inexpensive strawboard, and having a disk portion II and a peripheral flange ii. The disk portion is preferably inwardly eoncaved or dished slightly in order that it may have somewhat'of a bellows action and thus permit the closure to more readily acconimodate pressures which may be set up within the can of which the closure forms a part. The

.margin of the disk portion ll may bev inclined upwardly and outwardly as at l3 so as to provide a conical portion which terminates in the flange l2. Thus, at the juncture of the disk portion and v the flange, an internal annular channel is provided, one wall of which is formed by the flange l2 and the other wall of which is formed by the tapered or conical portion l3 of the disk.

' The closure further includes an oilproof membrane entirely covering the inside of the bodymember in including the inner surface of the to form a sealing bead between the end of the.

can body and the closure when the closure is heat-sealed to the can body.

In the embodiment of the: invention shown in Figs. 1 and i, the membrane constitutes a coating ll of an oil-proof, film-forming, thermoplastic adhesive which covers the exposed inside surface of the flange i2 and the bottom surface of the disk portion ll of the body member IO, and this coating is of substantially increased thickness at the juncture of the flange and the disk portions so as to provide an annular ring H which, as hereinafter described, forms a sealing 90 and corresponds in shape to, the body member.

bead or fillet between the closure and the end of the can body on which it is assembled.

The improved closure shown in Figs. 1 and 2 may be very economically and readily manufactured by passing a strip of fibrous material (hereln referred to as cap stock) through a cap press of conventional design whereby blanks are cut out from the strip and drawn to the shape illustrated in Fig. l of the drawings. ,After the body members are thus formed, a quantity of oilproof, thermoplastic, film-forming adhesive is applied to the entire inner surface of the body member and in such manner that an annnular ring or gasket i4 is formed at the juncture of the flange and the disk portion. This may be done by depositing a measured amount of thermoplastic material onto the disk at the center thereof and rapidly rotating the closure so as to cause the thermoplastic material, due to centrifugal force, to flowoutwardly of the disk and up along the flange. when rotation ceases, the excess material will collect at the juncture of the flange and disk portion and form the annular ring or gasket l4. The'thermoplestic coating is permitted to cool and harden. The closures are now complete and may be handled and shipped as unitary structures ready to be applied to the can bodies at the point at which the containers are filled.

In Fig. 2, the closure of Fig. 1 is shown as having been applied to a can body 25 which may be of any suitable construction but which is here shown as having a body portion of suitable fibrous material, such as inexpensive chipbou'd, which may be wound into a plurality of plies to provide the desired strength and bulk. The can body is shown as having a lining 26 which may com- 55 prise a sheet of oil impervious material adhesively secured to the inner surface of the body portion of the can. In application, the closure is slipped over the upper end of the can body heat-sealed thereon by means of a heated pressure ring which contracts the flange of the closure against the outside surface of the can body and at the same time applies heat to the flange. The thermoplastic coating, together with the annular ring it thereof, is rendered viscous and tacky and, during the sealing operation, the closure and can body are urged axially towards one another with the result that the end edge of the can body becomes embedded in the annular ring ll of the thermoplastic material and causes the excess thermoplastic material thereof to form a "fillet or gasket in the corner between the inside surface of the can body at one end thereof and.

margin. of the disk. When cooled, the thermoplastic coating. forms a very tight and secure I bond between the flange of the closure and the can body, and the fillet forms an eflective seal 5 which prevents the contents of the can from seeping up along the inside surface of the can to the raw edge of the can body. This fillet tapers down and spreads out along the inside wall of the can body and inwardly of the disk portion of the body member l0.

13 of being constituted of only the thermoplastic coating I4, also. comprises a lining i6 of a thin flexible oilproof sheet material, such as Cellophane. In each of the embodiments of Figs. 3 and 4, the lining is preferably coextensive with,

It fits within the body member. By preference, there is provided between the opposed surfaces of the flanges of the lining member and the body member a film ll of adhesive material, and this adhesive material, in the event that it is desired to permanently secure theflanges of the lining and the body member, is preferably of a thermoplastic nature and, sufficient quantity to serve the purpose stated but, in the event that it is 80 desired to provide a closure, the body member of which may be easily removed from the linin after the closure has been applied to the can body, the adhesive may be of such nature or of such small amount as to secure the flanges to- 85 gether only to the extent that the parts will not separate during handling and will permit the body member to be easily removed from the lining without disturbing the relation of the lining to the can body. In the drawings, the film or layer H of adhesive material is shown as being interposed between the disk portions of the body member and the lining as well as the flanges thereof; By preference, and for a purpose later described, the disk portion of the lining is not adhesively secured to the disk portion of the body acter of, and applied in a manner similar to, the

coating of the flrstembodiment. This coating is of thermoplastic, film-forming adhesive and covers the exposed surface'of the flange of the lining and extends onto the disk portion thereof,

tially increased thickness at the juncture of the flange and disk portions of the lining so as to provide the annular ring N. In Fig. 4, the coating of thermoplastic, film-forming adhesive cov- (which may first befilled with liquid) and is then erg t ti tt surface of t disk portion of the lining so that the lining is rendered tougher and stronger throughout. However, where it is desirable to save expense in the amount of the thermoplastic adhesive employed, the coating,

may extend only partially onto the disk portion of the lining, the central portion of the disk being free of suchcoating, as shown in Fig. 8. v

The improved closures, shown in Figs. 3 and 4.

may be very economically and readily manufactured by proceeding in accordance with the following preferred method: A strip of fibrous material, herein referred to as cap stock, and from which the body members are to be formed, may be first coated with a thin layer of thermoplastic the inside swam the My member at the adhesive and, after the adhesive has thoroughly the coating in each instance being of substen- 'iorming to the shape of the recess.

dried, a sheet of thin oilprooi sheet material; such as Cellophane, is laid on top of the cap stock with the adhesive coating between the two sheets. Of course, if desired, the thin layer of thermoplastic adhesive may be applied to one sideof the Cellophane lining instead of the stock material. The superimposed layers are then run throtlgh a cap press of conventional design. This press may have a female die provided with a recess corresponding in shape and size to the external shape of the closure to be formed, and a male die con- As the die members are brought together, they cut from the superimposed layers a-blank and draw the blank to the shape illustrated. During the cap drawing operation, heat is generated due to friction at 'the flange forming portions of the die members so that the adhesive between the flanges of the body member and lining is rendered yiscons and tacky with the resultthat it will adhere to both of the opposed surfaces of the flanges. Then, when the cap is-ejected from the female die, the adhesive is allowed to cool and harden so that the flanges of the body portion and lining are adhesively secured together sufliciently to keep the Cellophane and body member together until the cap is used. During the operation of drawing the closure to form, there is. not .suflicient heat generated .to render the adhesive l1 between the disk portions of the body member and the lining tacky so that in the finished closure the disk portions will not be adhesively securedtogether, that is, they are substantially loose of one another, as indicated by the space shown in Fig, i therebetween. After the closures are thus formed, a quantity of an oilproof thermoplastic film-forming adhesive is applied to the lining to form the coatingll'with the annular ring or gasket ll at the juncture of the flange and the disk portion of the lining. This may bev done by depositing ameasured amount of thermoplasticmaterial on the disk portion and theri rotating the closure, as described in connection with the embodiment shown in Fig. 1. In case it is not desired to cover the entire disk portion of the lining, asshown in Fig. 3, the measured amount of thermoplastic material is deposited onto the disk portion of the lining at a point oil center thereof. The thermoplastic coating is permitted to set. The closures are now unitary structures ready to be applied. V

The closures shown in Figs. 3 and 4 are applied to the end of the can body in a manner similar to that described in connection with the first embodiment of the invention. The cap is slipped over the end of the can body and is then heatsealed thereon by means of apressure ring. so heat-sealing the ring, if the adhesive layer H between the flanges of thebody member and the lining i6 is of a thermoplastic nature and is sumcient in quantity, it is rendered viscous and tacky so that a strong bond is obtained therebetween after cooling. Further, during such heat-seal: ing, the closure is moved downwardly over the from seeping up along the side of the inside of the can to the raw edge of the can body.

From the foregoing description taken in connection with the accompanying drawings, it will be seen that in each embodiment of the invention I provide a very simple and effective can closure which may be manufactured of relatively cheap materials and which may be economically made at a high rate of production. The closures may be handled and shipped as complete structures ready to be applied to the cans at the factories or places at which the cans are filled. Furthermore, the caps may be very quickly and readily applied to the can bodies after the latter are filled and,.when so applied, ail'ord very effective, strong and sturdy closures. In each instance, the closure has on its under face a membrane coextensive therewith, and the membrane is of an oilproof character so as to render the body portion of the closure impervious to oil. Furthermore, in each instance, the thermoplastic gasket at the corner between the disk portion of the can and the inside wall of the can body forms an effective seal which prevents seepage or leakage. This gasket further. has the advantage in that it is resilient and yet tough and, therefore, will absorb shocks and strains exerted on the corher of the closure and thus aid in preventing top edge of the can body, so as to embed that 1 edge into the annular ring H of the thermoplastic material so that a fillet or gasketis formed between the inside surface of the can body at the secure bond between the flange of thelining l4 and the can body, and the i'lllet forms an effective seal which prevents the contents of the can rupture or breaking of the closure.

Where a lining I8 is providedfas shown in Figs. 3 and 4, the disk portions of the body member and, the lining of the closure are, as previously, stated, not securely bonded together, and the obat any locality. Such sharp bending or creasing of the body member is almost bound tooccur from blows received during shipping or in careless handling of the filled cans. I have found from very extensive drop tests that in cases where the disk portion of the lining is closely bonded to the disk portion 'of the body member and the cap stock is severely or sharply bent (although it'is not ruptured), a microscopic rupture of the lining material frequently occurs which permits oil to leak through into contact with the cap stock, thus causing wicking. This does not occur where the disk portion of the lining is relatively free of the cap stock. I have further .found from these drop tests that the canmay be dropped many, times without completely rupturing the cap stock but upon further dropping of the can a point is reached where the cap stock is actually ruptured but, even in these instances, the lining has not been adversely affected or ruptured and the effective seal still remains so that the contents of the can cannot leak or seep out.

As many changes could be made in the aboveconstruction and many apparently widely .different embodiments of this invention could be made withoutdeparting from the scope thereof,

used in the following claim is intended to cover all of the generic and specific teaturesiot the invention herein'describedand all statements of the scope of they invention which, as a matter of language, might be said to fall therebetween.

I claim as my invention: A closure for closing flbrous' container bodies for the packaging of oil or the like, said closure comprising a body member having ,a disc for 5 covering the top of the container and a peripheral flange adapted to engage the exterior of a container body, said disc being depressed inwardly to provide a central portion and a circumferential channel between the flange and central portion, a coating oi normally non-viscous thermoplastic adhesive material on the inner face of the flange and the disc, said coating in the channel being of increased thickness to substantially fill the channel, said material being of the type which becomes viscous and tacky upon application of heat to provide a resilient sealing bead in the comer between the inner surface of a container body and the inner face of the disc of the closure when the closure isheat sealed to a conlQ tainer body.

ALEXANDER G. HATCH.

Images