US3912110A

US3912110A - Apparatus for closing drums

Info

Publication number: US3912110A
Application number: US362316A
Authority: US
Inventors: Wilhelm Hammes
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-05-30
Filing date: 1973-05-21
Publication date: 1975-10-14
Anticipated expiration: 1992-10-14
Also published as: SE398481B; MY8100081A; ES217360Y; FR2186388A1; ATA452373A; CH557264A; BR7303971D0; JPS4961261A; IT986691B; ES217360U; FR2186388B1; NL7307317A; GB1430983A; DE2226217A1; BE800254A; AT344070B

Abstract

A method and apparatus for closing the ends of plastic bung or stopper drums. The apparatus comprises an end closing coupling for a bung drum composed of plastic material wherein the upper edge of the body of the drum has a circumferential bordure including an inwardly projecting groove and an inwardly bent edge. An end closure for the bung drum is fashioned with a circumferential marginal bead having grooves operable to receive the inwardly projecting groove and inwardly bent edge of the drum body. The method comprises engagement of the inwardly projecting groove and bent edge with corresponding portions of the end closure marginal bead when the inwardly projecting groove and bent edge are in a warm state and subsequently cooling the projecting groove and bent edge to provide a secure shrink fit closure coupling.

Description

United States Patent [1 1 Hammes 1 Oct. 14, 1975 1 APPARATUS FOR CLOSING DRUMS [76] Inventor: Wilhelm Hammes, Hauptstrasse 38,

[30] Foreign Application Priority Data May 30, 1972 Germany 2226217 [52] US. Cl. 220/67; 220/76; 220/307; 220/308 [51] Int. C1. B65D 39/00; B65D 7/42 [58] Field of Search 220/24 A, 24 B, 24.5, 60, 220/76.67, 75, 66, 306, 307, 308; 215/41, 47

[56] References Cited UNITED STATES PATENTS 2,674,472 4/1954 Meyer 215/47 2,872,060 2/1959 Brune et al.. 215/47 3,531,013 9/1970 Hammes 220/55 AN 3,542,913 12/1967 Robinson et a1. 220/60 R 3,771,681 11/1973 Mart 215/41 3,780,897 12/1973 Wassiliefi 1 215/41 3,792,797 2/1974 Mrusek et a1. 220/60 R FOREIGN PATENTS OR APPLICATIONS 557,424 2/1957 Italy 215/364 524,500 12/1953 Belgium 215/364 769,054 2/1957 United Kingdom 215/364 77,929 4/1955 Netherlands 215/364 Primary Examiner-William 1. Price Assistant Examiner.loseph M. Moy

Attorney, Agent, or Firm-Burns, Doane, Swecker &

Mathis 57 ABSTRACT A method and apparatus for closing the ends of plastic bung or stopper drums.

The apparatus comprises an end closing coupling for a bung drum composed of plastic material wherein the upper edge of the body of the drum has a circumferential bordure including an inwardly projecting groove and an inwardly bent edge. An end closure for the bung drum is fashioned with a circumferential marginal bead having grooves operable to receive the inwardly projecting groove and inwardly bent edge of the drum body.

The method comprises engagement of the inwardly projecting groove and bent edge with corresponding portions of the end closure marginal bead when the inwardly projecting groove and bent edge are in a warm state and subsequently cooling the projecting groove and bent edge to provide a secure shrink fit closure coupling.

7 Claims, 1 Drawing Figure U.S. Patent Oct. 14,1975

APPARATUS FOR CLOSING DRUMS BACKGROUND OF THE INVENTION The invention relates to a bung drum which comprises a drum body made of thermoplastics by a blowmolding process and an end closure produced by way of an injection molding process.

Bung drums made of plastics which have become known hitherto are typically made in one piece by a blow-molding method, whereby one or two bungs or stoppers are configured in the mold parting line. These stoppers mostly are located in corresponding recesses of an end closure so as to provide a flat stacking surface. For reasons of stress distribution under a stacking load such drums, in most cases, are made with a slight bulge and at the transition to the lower and upper end closures they are given relatively large radii. Such drums with their contours rounded and smooth on all sides are very difficult to manipulate as compared to steel, metal drums which are provided with drawn-in bottoms and a folded edge, as is prevalent in the case of large volumes. The customary blown-in gripping troughs at the upper end of the jacket offer only an insufficient possibility for manipulating and they weaken the statics of the drum in an unjustifiable manner.

One solution which has been at least theorized is to provide a tip stretched crane ring on the upper closure. Such a device, however, is not suitable for widespread manipulation by hand. Moreover, the upper closure of such a drum broken up by the crane ring does not have the required strength in the case of a strain when fallmg.

The bungs or stoppers which were formed during blowing by molding of the hot material cannot be produced with the necessary precision because of the shrinking process and tensions which develop during cooling off. Mostly crooked or oval bungs develop which require special embodiments of bungs in order to bridge the clearance which then, however, will not permit the use of a large number of existing devices for filling, closing, sealing and emptying of drums. The upper end closure, which may be uneven because of the same reasons and is moreover increasingly exposed to abrasion, does not permit the often used marking with the designation of the filling material and with instructions for use. Likewise, the frequently used loading by means of vacuum lift is impossible because of the uneven upper end closure.

Another very serious disadvantage of such drums results from the process of production during which a parison of plastic material is squeezed off at both ends, is welded and is then blown against the inside wall of the mold. As a result of the squeezing out at the two ends this preform is no longer rotationally symmetric at the decisive points as a result of which differences in the thickness of the wall result during blowing because of the succeeding uneven stretching of the material, which differences can range within the order magnitude of 1:3. Particularly on the upper end closure, where for purposes of forming the bungs lying close to the edge, the parison must additionally be expanded, these differences in the thickness of the wall occur in an extreme form. In order to fulfill, in the case of drums produced in this way, the requirement for a minimum of the thickness of the wall, a disproportionally high consumption of material is required which, beside considerable additional costs, also reduces the efficiency of the production. Thus it has also turned out that drums with lids with an approximate full opening where the preform is squeezed off only at the lower end closure have a considerably better distribution of the thickness of the wall and can be produced considerably more quickly.

MAJOR OBJECTS AND BRIEF SUMMARY OF THE INVENTION Therefore, the invention is based on the objective of developing a bung drum which has on the one hand an almost even thickness of the wall corresponding to the standards known for open head drums and on the other hand permits easy and safe handling as a result of an encircling reinforced bead at the edge of a recessed upper bottom. Beyond that the requirements, such as the use of standard bungs, the possibility to take markings on the upper bottom and the use of vacuum lift during loading should also be fulfilled at the same time.

According to the invention, these and other objectives are achieved by a bung drum made of plastics with one or more bung openings. This bung drum at its upper edge of the body of the drum blow-molded out of thermo-plastic material has a groove-like bordure with an inwardly drawn groove and a likewise inwardly bent edge which engages with the corresponding grooves by way of the anticlinal bulge of the groove projecting inwardly and the inwardly directed upper edge, which grooves are disposed in the outside surface of an edge bead circling the upper end closure and which forms with said bead a perpendicular undissolvable connection.

The body of the bung drum according to the invention is to consist of thermoplastics, as for example the high molecular high density polyethylene, and advantageously it is produced according to the previously mentioned blow-molding process, whereby the preform is squeezed off only at the lower end closure while at the upper edge of the body of the drum the approximate full opening is maintained.

According to the invention the upper edge of the body of the drum is supposed to have a groove-like bordure with an inwardly drawn-in groove and an inwardly bent edge. Advantageously the groove-like bordure constitutes one piece with the body of the drum and is molded together with the latter.

Basically the bordure can have any given shape as long as it has an inwardly drawn groove and an inwardly bent edge. A groove-like bordure which is developed S-shaped has proven itself particularly well. For this purpose the upper edge of the body of the drum is first drawn-in groove-like to a bead projecting inwardly and, after a groove-like annular recess arched outwardly to a bead, it is again bent inwardly perpendicularly to the axis of the body of the drum. The groove drawn inwardly together with the bead arched outwardly and disposed above it and the drawn-in upper bottom form a sure possibility for gripping for the purpose of handling the bung drum according to the invention by hand. The safety of the grip can be improved still further by outside perpendicular corrugation of the bead arched outwardly and of the inside surface of the edge of the upper bottom.

With the bead-like arching projecting inwardly and the inwardly directed upper edge, the bordure engages with the grooves which are disposed in the outside surface of an edge bead circling the upper bottom. For this purpose the upper bottom is advantageously developed as a drawn-in bottom which is provided with a marginal bead which stands perpendicularly in relation to the upper surface of the upper bottom and which constitutes one piece with the latter. At the perpendicular outside of this marginal bead two encircling grooves have been disposed. The lateral parts limiting these grooves project from the marginal beads of the upper bottom and encircle the latter annularly. The said elements disposed in the middle part of this marginal bead can be connected with perpendicular bridges in order to counteract the distortion of the marginal bead of the upper end closure.

Advantageously the upper end closure is produced by way of an injection molding method, whereby the bungs are configured in the entry of the upper end closure for a better sealing of the connection between the bordure and the marginal bead. At the upper end closure a gasket can be inserted in at least one of the grooves circling the marginal bead of the upper end closure preferably into the upper one, which gasket is pressed by the engaging part of the bordure firmly against the inner surface of the pertinent groove. The gasket preferably has a round cross section and can consist of traditional, especially elastic material. Gaskets made of foam rubber and of foamed polyurethane have proven themselves particularly well.

For the production of the bung drum the parts of the bordure at the upper edge of the body of the drum projecting inwardly, are made to engage in a warm state with the grooves of the marginal bead disposed on the upper bottom and are then cooled.

THE DRAWINGS The design of the engaging elements of the head of the drum and the upper bottom can take place naturally in many different ways. In this respect, the drawing merely shows one embodiment of the bung drum according to the invention by way of example.

DETAILED DESCRIPTION The body 1 of the drum 'forms one piece with the S- shaped bordure 2. The bordure 2 has a bead-like bulge or arching 3 projecting inwardly and a generally radially inwardly directed edge or lip 4 which is separate from the bead-like arching 3 by an outwardly arched groove 5. The groove 5 is formed by an intermediate portion of the bordure and extends generally radially outwardly. The bead-like arching 3 forms on the outside an inwardly drawn groove 18 extending in a generally radial direction, which serves as an encircling gripping recess. In addition, the outside of the bordure 2 is provided with a corrugation 17. The drawn-in upper bottom 6 is provided on the outside surface with the marginal bead 7 with the

grooves

8 and 9, which are limited by and thus defined by axially spaced

lateral flange parts

10 and 11 or 12 and 13. These flange parts extend generally radially outwardly to define the generally radially inwardly projecting

grooves

8 and 9. A gasket 14 is inserted into the groove 9. The

lateral parts

11 and 12 are connected by bridges 15 at intervals. In the entry of the upper bottom 6, bungs 16 have been provided. The inside surface of the marginal bead 7 is likewise provided with a corrugation 17.

In order to establish the connection between the body 1 of the drum and the upper bottom 6, the latter is inserted into the warm bordure 2 in such a way that the inwardly projecting arching 3 and the inwardly bent edge 4 ofthe bordure 2 are caught easily by the

grooves

8 and 9 of the marginal bead 7 located on the upper bottom 6. The outside diameter of the lateral part 11 and of the bridges 15 is kept smaller than the outside diameter of the lateral part 12, as a result of which a safe guidance results during insertion and subsequent engagement of the upper bottom 6 with the bordure 2. As a result ofa subsequent cooling of the bordure 2 the latter shrinks to such a point that the projecting arching 3 is firmly pressed into the groove 8 and the inwardly bent edge 4 into the groove 9. In this fashion, and as can be viewed in the figure, the flange parts 10 and 11 extend radially outwardly beyond the radial inner extent of the bulge 3 such that these flange parts 10, 11 firmly engage opposite, longitudinally spaced

surfaces

20 and 21, respectively, of the bulge 3. Likewise, the

flange parts

12 and 13 extend radially outwardly beyond the radial inner extent of the lip 4 such that these flange parts l2, l3 firmly engage opposite, longitudinally spaced

surfaces

23 and 24, respectively, of the lip 4. The

flange parts

11 and 12 are, in this embodiment, both received within the groove 5. The trimmed and thus completely smooth front surface of the edge 4 at the same time compresses the gasket 14 so that a safe seal of the connection is guaranteed. The outwardly arched groove 5 of the bordure 2 of the drum is filled by the two

lateral parts

11 and 12 of the

grooves

8 and 9 which are connected for the purpose of reinforcement with a number of bridges 15 disposed at a distance from one another. The L-shaped lateral part 10 of the groove 8 engages below the bead-like arching 3 of the bordure 2 projecting inwardly and causes a double anchoring of the upper bottom 6 in the bordure 2 of the body 1 of the drum. The corrugation 17 on the bordure and on the inside surface of the marginal bead 7 increases the non-slipping quality and thus the possibility for handling of the drum according to the invention which is still further improved by the encircling gripping recess 18.

SUMMARY OF MAJOR ADVANTAGES OF THE INVENTION The grooves and projections of the bordure of the drum and the upper end closure being engaged with one another, together constitute a massive rim the outside surface of which advantageously is roughened or corrugated. This massive rim strengthens the head of the drum decisively beside offering an ideal possibility for handling and with its high stiffness it counteracts especially the feared distortion in the case when dropping down. Whenever the upper end closure is produced by way of the injection molding method, the bungs which have been also molded by the same process are of a considerably higher precision and permit the use of standard bung plugs and sealing caps. Moreover they arein a protected position in the entry of the upper end closure which on its part is completely even and thus can also be written on and permits the use of vacuum lift for loading.

Thus the invention makes use of the effect that blowmolded hollow bodies made of thermoplastics have after the blow-molding process a considerable linear delayed shrinkage, which moreover is fairly exactly determinable by partial control of the ejection temperature and variation of the thickness of the wall and which can amount to up to 3% of the diameter in the case of a circular cross section. In. the case of a drum opening of 500 mm diameter an engagement between the bordure of the drum and the upper bottom of 7.5 mm thus results at both sides, a measurement which is fully sufficient for a safe connection of the two parts. Since, in the case of the drum according to the invention, there is an absolutely even thickness of the wall in the middle and the upper area of the drum, the required consumption of material will thereby be reduced considerably. At the same time and as a result of the lower weight of the body of the drum, as a result of the fact that the upper bottom is missing and as a result of the cooling which is more free of tension, the performance of the blow-molding machine increases considerably, so that despite the additional manufacture of the upper bottom by way of the injection molding process, considerable technical and economic advantages result in accordance with the method of operation of the invention.

What is claimed is: 1. A drum of the type having a plastic body portion and a separate plastic closure firmly seated within an end of the body portion, the improvement wherein:

said plastic body portion has an end which defines a groove-like border including: an inwardly projecting circumferential bead-like bulge,

said bulge defining a generally radially inwardly projecting annular gripping recess;

an inwardly bent circumferential lip located outwardly of said bulge relative to a longitudinal axis of the drum, and

an intermediate section extending between said bulge and said lip and defining a generally radially outwardly projecting annular first groove; and

said plastic closure having circumferential margin means firmly anchored within said groove-like border of said body portion to seal and resist distortion of the latter while preventing removal of said closure from said body portion, said margin means comprising:

a generally radially inwardly projecting annular second groove defined by axially spaced, generally radially outwardly extending flange parts, with said bulge being seated within said second groove, and said flange parts each extending radially outwardly beyond the radial inner extent of said bulge such that said flange parts firmly engage opposite, longitudinally spaced surfaces of said bulge;

a generally radially inwardly projecting annular third groove located outwardly of said second groove relative to a longitudinal axis of the drum, said third groove being defined by axially spaced, generally radially outwardly extending flange parts, with said lip being firmly seated in said third groove; said last-named flange parts each extending radially outwardly beyond the radial inner extent of said lip such that said last-named flange parts firmly engage opposite, longitudinally spaced surfaces of said lip;

said first groove of said body portion being configured to receive at least one of said flange parts.

2. Apparatus according to claim 1 wherein the generally radial inward extent of said bulge is greater than that of said edge; and the generally radial outward extent of said flange parts progressively increases from the axially innermost flange to the axially outermost flange to facilitate installation of said cover into said drum.

3. A drum as defined in claim 1 wherein said flange parts comprise:

first and second axially spaced flange parts forming said second groove, and

third and fourth axially spaced flange parts forming said third groove;

said second and third flange parts being disposed axially between said first and fourth flange parts and being received in said second groove of said body portion;

said second flange part terminating short of said third flange part in a generally radially outward extent to facilitate installation of said closure.

4. A drum as defined in claim 3 wherein a series of annularly spaced bridging brace elements are provided interconnecting said second and third flange parts.

5. A drum as defined in claim 1 further including a gasket disposed in at least one of said second and third grooves in sealing relationship between said cover and said body portion.

6. A drum as defined in claim 1 and further including corrugations on an outside surface of said border of said body portion and on an inside surface of said margin of said closure to facilitate handling of said drum.

7. A drum of the type having a plastic body portion and a separate plastic closure firmly seated within an end of the body portion, the improvement wherein:

said plastic body portion has an end which defines a groove-like border including: an inwardly projecting circumferential bead-like bulge, said bulge defining a generally radially inwardly projecting annular gripping recess; an inwardly bent circumferential lip located outwardly of said bulge relative to a longitudinal axis of the drum, and an intermediate section extending between said bulge and said lip and defining a generally radially outwardly projecting annular first groove; and said plastic closure having circumferential margin means firmly anchored within said groove-like border of said body portion to seal and resist distortion of the latter while preventing removal of said do sure from said body portion, said margin means comprising: a generally radially inwardly projecting annular second groove defined by axially spaced, generally radially outwardly extending first and second flange parts, with said bulge being seated within said second groove, and a generally radially inwardly projecting annular third groove located outwardly of said second groove relative to a longitudinal axis of the drum, said third groove being defined by axially spaced, generally radially outwardly extending third and fourth flange parts, with said lip being firmly seated in said third groove; said second and third flange parts being disposed axially inwardly between said first and fourth flange parts and being received in said second groove of said body portion;

said second flange part terminating short of said third flange part in a generally radially outward extent to facilitate installation of said closurev

Claims

1. A drum of the type having a plastic body portion and a separate plastic closure firmly seated within an end of the body portion, the improvement wherein: said plastic body portion has an end which defines a groove-like border including: an inwardly projecting circumferential bead-like bulge, said bulge defining a generally radially inwardly projecting annular gripping recess; an inwardly bent circumferential lip located outwardly of said bulge relative to a longitudinal axis of the drum, and an intermediate section extending between said bulge and said lip and defining a generally radially outwardly projecting annular first groove; and said plastic closure having circumferential margin means firmly anchored within said groove-like border of said body portion to seal and resist distortion of the latter while preventing removal of said closure from said body portion, said margin means comprising: a generally radially inwardly projecting annular second groove defined by axially spaced, generally radially outwardly extending flange parts, with said bulge being seated within said second groove, and said flange parts each extending radially outwardly beyond the radial inner extent of said bulge such that said flange parts firmly engage opposite, longitudinally spaced surfaces of said bulge; a generally radially inwardly projecting annular third groove located outwardly of said second groove relative to a longitudinal axis of the drum, said third groove being defined by axially spaced, generally radially outwardly extending flange parts, with said lip being firmly seated in said third groove; said last-named flange parts each extending radially outwardly beyond the radial inner extent of said lip such that said last-named flange parts firmly engage opposite, longitudinally spaced surfaces of said lip; said first groove of said body portion being configured to receive at least one of said flange parts.

3. A drum as defined in claim 1 wherein said flange parts comprise: first and second axially spaced flange parts forming said second groove, and third and fourth axially spaced flange parts forming said third groove; said second and third flange parts being disposed axially between said first and fourth flange parts and being received in said second groove of said body portion; said second flange part terminating short of said third flange part in a generally radially outward extent to facilitate installation of said closure.

7. A drum of the type having a plastic body portion and a separate plastic closure firmly seated within an end of the body portion, the improvement wherein: said plastic body portion has an end which defines a groove-like border including: an inwardly projecting circumferential bead-like bulge, said bulge defining a generally radially inwardly projecting annular gripping recess; an inwardly bent circumferential lip located outwardly of said bulge relative to a lonGitudinal axis of the drum, and an intermediate section extending between said bulge and said lip and defining a generally radially outwardly projecting annular first groove; and said plastic closure having circumferential margin means firmly anchored within said groove-like border of said body portion to seal and resist distortion of the latter while preventing removal of said closure from said body portion, said margin means comprising: a generally radially inwardly projecting annular second groove defined by axially spaced, generally radially outwardly extending first and second flange parts, with said bulge being seated within said second groove, and a generally radially inwardly projecting annular third groove located outwardly of said second groove relative to a longitudinal axis of the drum, said third groove being defined by axially spaced, generally radially outwardly extending third and fourth flange parts, with said lip being firmly seated in said third groove; said second and third flange parts being disposed axially inwardly between said first and fourth flange parts and being received in said second groove of said body portion; said second flange part terminating short of said third flange part in a generally radially outward extent to facilitate installation of said closure.