Threaded closure

Dec. 7, 1965

3,221,920

A. BUYS

THREADED CLOSURE

Filed Nov. 28, 1962

Sheets-Sheet 1

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INVENTOR.

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A. BUYS

THREADED CLOSURE

Dec. 7, 1965

Filed Nov. 28, 1962

3,221,920

Sheets-Sheet a

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INVENTOR.

BY S ^y

United States Patent Office

3,221,920

Patented Dec. 7, 1965

3,221,920 THREADED CLOSURE

Adriaan Buys, Krommenie, Netherlands, assignor, by mesne assignments, to Inland Steel Company, Chicago, Ill., a corporation of Delaware ⁵

Filed Nov. 28, 1962, Ser. No. 240,529

Claims priority, application Great Britain, Nov. 29, 1961, 42,648/61

Claims. (Cl. 220—39)

The present invention relates generally to containers of the type having a sheet metal wall and, more particularly, to improved closure seats for such containers. In its principal aspects, the invention is concerned with closure seats for the bung-holes of such containers. 15

Heretofore, sheet metal containers of the type used for packaging, storing and shipping of various commodities, for example, oil and oil products, and other liquid, semi-liquid, pulverized or granular substances, have commonly been provided with an aperture or bung- 20 hole in one wall of the container, which bung-hole permits filling and emptying of the container. In order to allow closing and sealing of the container, a bung-hole bushing is generally mounted in the aperture and secured to the container wall. Such bushings are usually pro- 25 vided with internal screw threads adapted to receive an externally threaded bung or like closure member.

The manufacture of closure assemblies of the foregoing type has proved to be both laborious and costly, and has resulted in relatively heavy container constructions. 30 Moreover, many manufacturing and constructional problems have been encountered, particularly where the container wall thickness is relatively thin. In an effort to solve these problems, attempts have been made to provide a construction in which the separate bung-hole bushing 35 is dispensed with, for example, by forming the container wall with a closure seat which projects from and is integral with the container wall and which has screw threads pressed therein. However, it has been found that it is extremely difficult to press a sufficient number of ⁴⁰threads in the seat, each having a sufficiently sharp profile to afford a liquid tight seal with a conventional closure such as a screw threaded plug or cap.

Consequently, it has been proposed that container walls be provided with integral polygonal collars projecting therefrom and having screw threads pressed in the flat ⁴⁵sides thereof, thus forming a bung-hole closure flange having screw threads which are interrupted at equidistantly spaced points. Such a construction is disclosed in the copending application of Comelis Andrianus Meyer, Serial No. 825,910, filed July 9, 1959, now Patent No. ⁵⁰3,076,670. While this type of construction has proved satisfactory in many instances, the present invention provides still another solution to the problems which have heretofore plagued container manufacturers.

It is a general aim of the present invention to provide ⁵⁵an improved threaded closure seat which overcomes the foregoing disadvantages and which is characterized by its ease of manufacture.

A related object of the invention is to provide a threaded bung-hole closure flange which permits of economical ⁶⁰fabrication and which is characterized by its sturdiness and reliability in use.

More specifically, an object of the invention is to provide an integral closure seat for containers which greatly facilitates the formation of screw threads therein and ⁶⁵which permits such threads to be formed by relatively simple and conventional presses or like equipment.

An ancillary object of the invention is to provide a container having a threaded closure seat which permits the ready application of an effective tamperproof and pilfer- '° proof cap or sealing arrangement.

It is a more detailed object of the invention to provide an improved threaded closure seat for containers which positively and resiliently grips the mating removable threaded closure member.

In another of its important aspects, it is an object of the invention to provide an improved closure seating arrangement which permits the fabrication of a wide range of different size threaded closure seats suitable for receiving standard closure plugs or caps.

Yet another object of the invention is to provide an improved threaded closure seat which permits the use of a wide variety of different grades and gauges of sheet metal for the container wall construction.

Other objects and advantages of the invention will become apparent as the following description proceeds, taken in conjunction with accompanying drawings, in which:

FIGURE 1 is a plan view of a portion of a container wall after completion of the first stage of the method for manufacturing a closure seat in accordance with the invention, the seat here being adapted to receive a % plug;

FIG. 2 is a view similar to FIG. 1 of the same container wall portion after the second stage of the closure seat forming operation;

FIG. 3 is a perspective view of the container wall portion will a completed closure seat embodying the features of the invention formed therein;

FIG. 4 is a view similar to that of FIG. 1 illustrating the initial forming stage for a slightly modified seat construction, also embodying the invention, and particularly suitable for reception of a larger closure member, e.g., a 2 plug;

FIG. 5 is a view similar to FIG. 2 after the second stage of the forming operation performed on the modified seat;

FIG. 6 is a perspective view, partly in section of the completed modified form of closure seat;

FIG. 7 is an enlarged cross-sectional view of part of a closure assembly embodying the invention, here illustrating a closure plug and a seal cap applied to the seat; and

FIG. 8 is a cross-sectional view similar to that of FIG. 7 of another form of closure assembly also embodying the invention.

While the invention is susceptible of various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawings, there is illustrated a novel seating arrangement for mounting plugs, caps and similar closures in the bung-holes of containers employing sheet metal walls. For the purpose of simplifying the description and facilitating an understanding of the invention, the closure seating arrangement will hereinbelow be described in conjunction with exemplary methods for forming a screw threaded closure seat in a sheet metal wall 11 of a container (not shown). Such methods form the subject matter disclosed and claimed in the copending application of Adriaan Buys, Serial No. 447,938, filed March 17, 1965, and assigned to the assignee of the present invention, which copending application is a divisional application based upon the present application.

In accordance with one of the important aspects of the present invention, provision is made for stamping, cutting or otherwise forming a generally star-like opening in a container wall, the opening defining a plurality of tongues

3,321,920 «Ί» ο which are then pressed so as to form portions of screw threads and bent out of the plane of the wall 11 to define segments of a closure seat having an interrupted helical screw thread formed therein. In the exemplary form of the invention (shown in FIGS. 1-3 after completion 5 of sequential stages of the forming operation) the closure seat is formed in the wall 11 by creating a plurality of slots 12 extending substantially radially from a central point 18 or hole 13 in a star-like formation. The central hole 13 and the slots 12 may be formed in separate μ, operations if desired, but they are preferably formed simultaneously. The operation or operations to form the central hole and the slots may, as well known to those skilled in the art, be carried out by means of a punching press (not shown) including a punch or male member 15 having a cross-section corresponding to the shape of the hole with slots to be formed (for example, the hole 13 shown in FIGURE 1 which is provided with four such slots 12), and a die or female member having a hole of similar configuration, said members being reciprocable 20 with respect to one another,

In carrying out the present invention, provision is made for forming screw threads in the tongues 16 defined by the slots 12. To this end, and during the second stage of the operation, alternating grooves 14 and ridges 15 25 are pressed in the tongues 16 (FIGURE 2). As shown in the drawings, the distance between the grooves and the inner tips of the tongues (and thus also between the ridges and the inner tip of the tongues) gradually increases in a counterclockwise direction so that together 30 they define a generally angular or jagged spiral built up of straight line sections.

During the last stage of the forming operation, the tongue 16 are bent out of the plane of the container wall 11 until they project at substantially right angles from 35 the container wall, thus forming a closure seat integral with the container wall 11 (FIGURE 3). It will be observed that the grooves 14 and the ridges 15 in the tongues 16 together form a helix which defines either internal screw threads adapted to receive the external screw 40 threads of a closure plug (no shown) or external screw threads adapted to cooperate with internal screw threads of a closure cap (not shown).

In keeping with the invention, the tongue 16 are preferably bent slightly less than 90° out of the plane of the container wall 11 when the container is to be closed by means of a threaded plug. In other words, they slightly converge in a direction away from the container wall and therefore resiliently hold a plug screwed into the closure seating means with a force progressively increasing ₅₍₎towards the free extremities of the tongues.

Alternatively, if a screw cap is to be applied, the tongues 16 are preferably bent slightly over 90° out of the plane of the container wall 11 so that they slightly diverge in a direction away from the container wall.

While the exemplary closure construction has been illustrated and described in conjunction with grooves 14 and ridges 15 which constitute straight line portions of an angular spiral (thus the grooves and ridges form portions of a true common helix after the togues have θθ been bent at substantially right angles to the container wall), the grooves, and thus the ridges, may also form the sides of equilateral polygons of increasing sizes, so that the screw threads formed in the bent-over tongues are not truly helical but instead consist of “steps” ar- _c5ranged along a helical path. In this latter case the yielding and resilient nature of the tongues will allow adaption thereof to the truly helical screw threads of the closure member.

In carrying out the present invention, the marginal ₇₍₎edge 17 of the container wall 11 surrounding the feet of the tongues 16 and the dead ends of the slots 12 is also bent out of the plane of the container wall, thereby forming an uninterrupted annular connection between said tongues and the container wall proper (FIG. 3). This 75 annular connection may serve as a seat for a sealing gasket as will hereinafter be described, and to this end it is preferably formed with a curved cross-section (FIG. 7).

Referring to FIGS. 4-6 conjointly, there is illustrated a slightly modified closure seat which is generally similar to the seat described above. However, the modified form of closure seat is intended to receive a standard 2 plug, whereas the construction shown in FIGS. 1-3 is designed to receive a standard % plug. Accordingly, the central hole 13 in the modified construction is formed with a relatively larger diameter (suitable for reception of a 2 plug) in the order of 35 millimeters, whereas the slots have a relatively shorter length (in the order of 10-12 millimeters) as compared to the diameter of the hole. Moreover, eight slots 12 and consequently eight tongues 16 are formed in order to obtain a better approach to a purely cylindrical seat with less labor.

The tongues 16 bent out of the plane of the container wall 11 may be kept more or less in a flat condition, but as shown in the drawings they are preferably curved in a plane substantially parallel to the plane of the container wall, the concave side of the tongues being directed towards the center 18 of the closure seat. A particularly advantageous embodiment is that in which the tongues are bent into the shape of circular arcs having a radius R and all having their centers coinciding with the center 18 of the closure seat (FIG. 6).

In accordance with another of the important aspects of the present invention, means are provided for effecting a tamperproof and pilferproof sealed closure for containers employing screw-type plugs or caps. In the exemplary construction shown in FIG. 7, the container wall 11 is formed with a plurality of tongues 16 in substantially perpendicular relationship to the plane of the container wall and having portions of screw threads 14, 15 pressed or otherwise formed therein. The tongues are positioned in an annular configuration and thus constitute a closure seat adapted to receive a screw threaded closure plug 19. A sleeve 20 of rigid material such, for example, as sheet metal is inserted into the closure seat, a sealing gasket 21 having been interposed beforehand between the sleeve 20 and the uninterrupted curved annular connection 17 between the tongues 16 and the container wall 11 proper. As here illustrated, the sleeve comprises an annular portion extending from the exterior of the container to approximately the uppermost screw thread in the closure seat and having a flange-like outwardly extending top edge 22. The lower extremity of the sleeve 20 is serrated so as to form teeth 23 at least partially protruding into the slots 12 between the tongue 16. A second sealing gasket 24 is provided before the plug 19 is introduced into the plug seat. After the plug has been screwed home a seal cap 25 is placed on top of it and the peripheral edge of the cap is rolled, wheeled, pressed or by means of any other operation, bent over, around and under the top edge 22 of the sleeve 20, thereby providing a tamperproof and pilferproof seal since the cap has to be destroyed or damaged in order to enable removal of the plug 19.

As best illustrated in FIGURE 7, the teeth 23 of the sleeve 20 may be bent slightly outward after the sleeve is mounted in the closure seat. However, this operation can be dispensed with if desired inasmuch as the sleeve is held in place by the closure plug 19. However, it is essential that the teeth 23 of the sleeve 20 protrude or penetrate into the slots 12 between the tongues 16 so as to prevent relative rotational movement between the sleeve 20 and the wall 11. Otherwise, it would be possible to open the container by simply rotating the sleeve 20, and thus unscrewing the entire assembly consisting of the seal cap 25, the sleeve 20, the plug 19 and the sealing gasket 24.

A slightly modified form of tamperproof and pilferproof closure assembly is shown in FIG. 8. As here il3,221, 5 lustrated, the sleeve 20 is made of a yielding material such, for example, as a synthetic thermoplastic material which itself serves as a sealing gasket. Thus, the first sealing gasket 21 may be dispensed with. In certain instances, the second sealing gasket 24 may also be omitted. 5 In the modified construction shown in FIG. 8, the flange-like outwardly extending top edge 22 of the sleeve 20 may be formed with one or more holes 26 which serve to receive a sealing wire (not shown) threaded through a corresponding hole in the plug and the hole 26. When a sealing wire is employed, it is possible to eliminate the separate seal cap 25. This construction may, of course, also be employed in the construction shown in FIG. 7 where a sheet metal sleeve 20 is employed.

It will be apparent from the foregoing that there has 15 been provided a novel closure construction which permits of ease in manufacture, yet which provides an effective and positive means for securing threaded plugs or caps to the container wall. Moreover, the portions of the screw threads can be formed while the tongues are 20 still disposed in the plane of the container wall, thus permitting the use of conventional up and down presses or the like, rather than the relatively complex equipment required to form screw threads in an annular sleeve or collar. 25