GB1603973A

GB1603973A - Drums

Info

Publication number: GB1603973A
Application number: GB6149/78A
Authority: GB
Original assignee: American Can UK Ltd
Current assignee: American Can UK Ltd
Priority date: 1978-02-16
Filing date: 1978-02-16
Publication date: 1981-12-02
Also published as: ZA79541B; DE7810401U1; LU80903A1; FR2417439A1; IE790295L; CA1116109A; BE874254A; NL7901208A

Description

(54) IMPROVEMENTS IN OR RELATING TO DRUMS (71) We, AMERICAN CAN (U.K.) LIM- ITED, formerly Reads Limited, a British Company, of Orrell Lane, Liverpool L9 8BW, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention is concerned with improvements in or relating to drums.

A well known type of drum comprises a cylindrical metal body portion and opposed end portions connected to the body portion by seams.

One problem which arises with this type of drum, particularly in the larger sizes, is that the seams present an area of weakness liable to fail, for example on impact when the drum is dropped from a height.

It is an object of the present invention to provide a drum in which this problem is minimised.

Surprisingly, we have found that resistance to failure on impact can be enhanced by reducing the cross-section of the body portion adjacent the seams.

According to one aspect of the present invention there is provided a drum having a capacity of at least fifty litres and comprising a circular cylindrical predominantly smoothsided body portion of steel or aluminium, the wall thickness of the body portion being 0.4 to 1.6 mm., first and second end portions, a first interlocked seam connecting the first end portion to the body portion at one end of the body portion, a second interlocked seam connecting the second end portion to the body portion at a second end of the body portion, the first and second interlocked seams each having five or more layers, a first portion of the body portion adjacent the first seam and a second portion of the body portion adjacent the second seam, wherein each of the first and second portions of the body portion is necked-in so that the crosssection of the drum adjacent the seams is reduced and the seams lie wholly within the cylindrical axial extensions of the body portion, the first and second necked-in portions of the body portion each including a portion converging inwardly of the longitudinal axis of the drum and a substantially circular cylindrical shaped reduced diameter portion adjoining the seam, the first and second portions of the body portion being axially deformable whereby the interlocked seams can telescope within the body portion under impact to minimise damage to the interlocked seams.

The invention is particularly, but not exclusively, applicable to drums having a capacity of at least 200 litres.

For example the invention is applicable to drums having capacities from 50 to 250 litres.

Particular examples within this range include the following: 50 to 100 litres 100 to 150 litres 150 to 250 litres.

The wall thickness of the body portion generally increases with capacity, other factors being equal, and in the range from 50 litres to 250 litres the wall thickness varies from 0.4 to 1.6 mm.

The steel can be mild steel or stainless steel. The end portions can correspondingly be of mild steel, stainless steel or aluminium.

The above and other aspects of the invention will become more clear from the following description to be read with reference to the accompanying drawings. This description is given by way of example only and not by way of limitation of the invention.

In the accompanying drawings: Figure 1 shows a side view of a first drum embodying the invention; Figure 2 shows an enlarged sectional side view of a top seam of the drum shown in Figure 1; Figure 3 shows a plan view of the drum shown in Figure 1; Figure 4 illustrates an intermediate stage in the manufacture of the drum of Figure l; Figures 5 to 12 illustrate various modifications.

The first drum embodying the invention (Figures 1, 2 and 3), comprises a circular cylindrical metal body portion 10 having smooth sides and uniform cross-section, except for two outstanding ribs 12 located at a central region of the body portion. The drum also comprises a dished metal upper end portion 14, and an opposed metal lower end portion 16, which are connected to the body portion at the opposite ends thereof by seams 18, 20 respectively.

The body portion 10 is necked-in at 22, 24 adjacent the seams 18, 20, so that the crosssections at the seams are reduced, and are smaller than and lie wholly within the predominantly uniform cross-section of the body portion 10. The seams thus lie wholly within the cylindrical axial extensions of the body portion (See Figure 2). The necking-in results in a converging or frusto-conical configuration at 26, 28 adjacent each end of the body portion 10.The angle a to the vertical of each frusto-conical configuration 26, 28, that is, relative to the longitudinal axis of the drum, is between 5" and 60', preferably between 10' and 50', e.g. 30'; and the regions 27, 29 of the body portion 10 which lead from the frusto-conical configurations to the seams 18, 20, are substantially parallel to the main axis of the body portion 19 such as to comprise circular cylindrical shaped portions.

The seam 18 is an interlocked seam of known type having five layers, three from the end portion 14, and two from the body portion 10. The seam 20 corresponds in construction and arrangement to the seam 18.

The upper end portion 14 is circular (Figure 3), and comprises octagonal pressedup portions 30, 32, in which are provided threaded pour and vent openings 34, 36 respectively. The openings 34, 36 are closable by threaded plugs (not shown).

The lower end portion 16 corresponds in construction and arrangement to the upper end portion 14, except that there are no pour and vent openings or corresponding octagonal portions.

Both end portions 14 and 16 are dished inwardly of the respective seams 18, 20, and comprise outwardly domed central portions, as shown at 15 in Figure 2.

In the manufacture of the drum, the necking-in is obtained by carrying out a reduction operation using a roller necking tool or a segmental shrinking tool on the body portion 10, at positions which will be adjacent each seam 18, 20 when formed, and each reduction operation is carried out simultaneously with the provision of an outwardly extending flange (40 in Figure 4) which is subsequently folded over with metal of the end portion to form the seam. It will be noted that an actual reduction operation is involved at 22, 24, and the necking-in is not provided by outwardly expanding regions of the body portion 10,-complementary to the necked-in regions.

The extent of the necking-in is for exampie, such as to reduce the internal diameter of the body portion at the seam by up to 10%, 12% or 15% for smaller drums, and up to 5% or 7% for larger drums. Even bigger reductions are conceivable, e.g. up to 18G or 20%.

These percentages are calculated as D-d x 100, D where (Figure 2) d is the internal diameter at the seam, and D the internal diameter of the predominantly uniform cross-section of the body portion 10, and the "extent of neckingin" referred to hereinafter is thus accordingly so defined.

We believe that the drum embodying the invention has enhanced resistance to failure on impact, as evinced by standard drop tests, because the impact force is lessened by crushing provided by collapse at the metal folds 31 defining the upper and lower boundaries of the frusto-conical portion 26 or 28.

Lateral distortion of the seam 18 or 20 is reduced as the seam telescopes within the protection of the cylindrical body portion 10, leaving the inner juxtaposition of the seam and body portion relatively undistorted.

Also, the necking-in facilities safe handling of the drum by reducing the risk of finger entrapment by the seams.

The modifications shown in Figures 5 to 9 are applicable equally with the seam formation of Figure 2 or with a known seven layer interlocked seam (not shown) comprising four layers from the end portion and three layers from the body portion.

It is believed that the modifications of Figures 5 to 9 may provide additional strengthening characteristics, for example to resist axial compression in the thinner metal gauges.

In each of the modifications, the seaming and necking-in configurations are the same at both ends of the drum.

In the modification of Figure 5, the configuration 26 comprises three evenly stepped frusto-conical portions 26a, 26b and 26c.

In the modification of Figure 6, a plurality of evenly spaced axial notches 42 are indented in the body portion 10, and each notch extends across the boundary between the frusto-conical configuration 26 and an adjacent region of the body portion 10, which region is axially inward of said configuration. The width of each notch is approximately equal to the distance between adjacent notches.

In the modification of Figure 7, a plurality of evenly spaced pressed-out helical ribs 44 are provided on the frusto-conical configuration 26, the ribs 44 being inclined to the axis of the drum.

In the modification of Figure 8, a continuous pressed out sinuous rib 46 is provided on the frusto-conical configuration 26.

In the modification of Figure 9, an annular bead 48 is pressed upwardly in the domed portion 15 adjacent its periphery and radially inwardly of the seam.

Again, the modifications shown in Figures 10, 11 and 12 are applicable equally with the seam formation of Figure 2 or with a seven layer interlocked seam.

In each of the modifications of Figures 10, 11 and 12, the necking-in results in a converging configuration 126 adjacent the upper end of the body portion 10 which configuration is sinuous in a direction axial of the body portion; and a corresponding sinuous configuration (not shown) ajacent the lower end of the body portion 10. In Figure 10 the sinuous configuration is relatively abrupt; in Figure 11 it is much less abrupt; resembling a bottle neck to give high compression resistance; and the sinuous configuration of Figure 12 is intermediate those of Figures 10 and 11.

WHAT WE CLAIM IS: 1. A drum having a capacity of at least fifty litres and comprising a circular cylindrical predominantly smooth-sided body portion of steel or aluminium, the wall thickness of the body portion being 0.4 to 1.6 mm., first and second end portions, a first interlocked seam connecting the first end portion to the body portion at one end of the body portion, a second interlocked seam connecting the second end portion to the body portion at a second end of the body portion, the first and second interlocked seams each having five or more layers, a first portion of the body portion adjacent the first seam and a second portion of the body portion adjacent the second seam, wherein each of the first and second portions of the body portion is necked-in so that the cross-section of the drum adjacent the seams is reduced and the seams lie wholly within the cylindrical axial extensions of the body portion, the first and second necked-in portions of the body portion each including a portion converging inwardly of the longitudinal axis of the drum and a substantially circular cylindrical shaped reduced diameter portion adjoining the seam, the first and second portions of the body portion being axially deformable whereby the interlocked seams can telescope within the body portion under impact to minimise damage to the interlocked seams.

2. A drum according to claim I having a capacity from 50 to 250 litres.

3. A drum according to claim 1 having a capacity of at least 200 litres.

4. A drum according to claim 1, wherein the extent of necking-in as hereinbefore defined is 20No.

5. A drum according to claim 1, wherein the extent of necking-in as hereinbefore defined is 15%, 6. A drum according to any one of the preceding claims wherein the converging portion is frusto-conical and the angle (a) of the frusto-conical portion to the longitudinal axis of the drum is between 5" and 60 .

7. A drum according to claim 6, wherein said angle is between 10 and 50'.

8. A drum according to claim 7, wherein said angle is 304.

9. A drum according to claim 1, wherein the necking-in results adjacent each end of the body portion in a configuration comprising three stepped frusto-conical portions.

10. A drum according to claim 1, wherein the body portion comprises a plurality of axial notches, each of which extends across the boundary between a frusto-conical portion comprising the converging portion and an adjacent region of the body portion, which region is axially inward to the frustoconical portion.

11. A drum according to claim 1, wherein a frusto-conical portion comprising the converging portion is provided with a plurality of helical ribs inclined to the axis of the drum.

12. A drum according to claim 1, wherein a frusto-conical portion comprising the converging portion is provided with a continuous sinuous rib.

13. A drum according to claim 1, wherein the necking-in results in a converging configuration of the first and second end portions of the body portion which is sinuous in a direction axial of the body portion.

14. A drum according to claim 1, wherein the seam comprises five layers.

15. A drum according to claim 1, wherein the seam comprises seven layers.

16. A drum according to any one of the preceding claims, wherein the end portions are also of metal.

17. A drum according to any one of the preceding claims, wherein an annular bead is provided in at least one end portion radially inwardly of the associated seam.

18. A drum having a capacity of at least fifty litres with a wall thickness of its body portion of 0.4 to 1.6 mm. constructed and arranged substantially as hereinbefore described with reference to Figures 1, 2 and 3, or any one of Figures 5 to 12 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. of the drum. In the modification of Figure 8, a continuous pressed out sinuous rib 46 is provided on the frusto-conical configuration 26. In the modification of Figure 9, an annular bead 48 is pressed upwardly in the domed portion 15 adjacent its periphery and radially inwardly of the seam. Again, the modifications shown in Figures 10, 11 and 12 are applicable equally with the seam formation of Figure 2 or with a seven layer interlocked seam. In each of the modifications of Figures 10, 11 and 12, the necking-in results in a converging configuration 126 adjacent the upper end of the body portion 10 which configuration is sinuous in a direction axial of the body portion; and a corresponding sinuous configuration (not shown) ajacent the lower end of the body portion 10. In Figure 10 the sinuous configuration is relatively abrupt; in Figure 11 it is much less abrupt; resembling a bottle neck to give high compression resistance; and the sinuous configuration of Figure 12 is intermediate those of Figures 10 and 11. WHAT WE CLAIM IS:

1. A drum having a capacity of at least fifty litres and comprising a circular cylindrical predominantly smooth-sided body portion of steel or aluminium, the wall thickness of the body portion being 0.4 to 1.6 mm., first and second end portions, a first interlocked seam connecting the first end portion to the body portion at one end of the body portion, a second interlocked seam connecting the second end portion to the body portion at a second end of the body portion, the first and second interlocked seams each having five or more layers, a first portion of the body portion adjacent the first seam and a second portion of the body portion adjacent the second seam, wherein each of the first and second portions of the body portion is necked-in so that the cross-section of the drum adjacent the seams is reduced and the seams lie wholly within the cylindrical axial extensions of the body portion, the first and second necked-in portions of the body portion each including a portion converging inwardly of the longitudinal axis of the drum and a substantially circular cylindrical shaped reduced diameter portion adjoining the seam, the first and second portions of the body portion being axially deformable whereby the interlocked seams can telescope within the body portion under impact to minimise damage to the interlocked seams.