GB1572031A - Containers - Google Patents

Description

(54) CONTAINERS (71) We. METAL BOX LIMITED. of Queens House. Forbury Road. Reading RG1 3.1H. Berkshire. England a Britisch Company, 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 particularlv described in and by the following statement: This invention relates to containers having a bottom wall integral with a body wall and more particularly. but not exclusively. to can bodies drawn from sheet metal and cans having such bodies.

Cans for carbonated beverages such as beer and soft drinks are known. One such type of can has a body which is drawn and wall ironed from tinplate about 0.012" thick, to have the form ol a cylinder closed at one end by an integral bottom. the other end being necked and closed, after filling. by a so-called easy-opening can end of. for example. the well-known ring pull tvpe. Such can bodies have a thin cylindrical wall less than ().()()5" thick and a bottom wall of substantiallv the same thickness as the tinplate used to make the can body.

i.e. substantially unreduced in thickness during forming of the can body.

Beverage cans have to contain the internal pressure arising from carbonation of the contents and this may be as much as 100 p.s.i. In order to do this can bodies have been proposed and/or made, having a concave, upwardly-domed bottom. However, largely in order that the diameter of this dome shall not be too large, and therefore inhently weak when made of tinplate of the order of 0.012" thick, the thin side wall of the body is joined to the concave dome by a channel portion, akin in principle to the "anti-peaking" beads used in some known types of easy-opening end.This channel portion is, in at least one published design, in the form of three distinct portions, namely an outer frustoconical portion extending downwardly and inwardly from the cylindrical side-wall towards the axis of the body: a stand bead portion joined thereto: and an inner portion which extends from the bead upwardly and inwardly to join and support the periphery of the concave dome. The concave dome is of such a curvature that the top of the dome extends to a height. at the axis. above that at which the cylinder wall joins the outer frusto-conical portion. Such domed can ends ire substantially rigid in use.However such high concave domes encroach wastefully upon the container volume and if accidentally subjected to pressures beyond that which they are designed to contain. they may evert catastrophically and permanently to a shape which does not allow them to stand upn.ghtly upon the stand bead.

The present invention provides a metal container body having a thin cylindrical side wall closed at one end by a bottom all thicker than the side wall and integral therewith: the bottom wall including a substantially rigid annular channel portion, upon which the body is capable of standing. and a flexible panel portion: said channel portion having an outer portion, a stand bead and an inner portion: said outer portion extending axially and inwardly from the cylindrical side wall to the stand bead and said flexible panel portion including a flat central panel portion surrounded by an upwardly projecting downwardly concave annular bead connecting directly with the inner channel portion: said flexible panel portion being wholly within the axial height of the channel portion as defined between the junction of the cylindrical side wall to outer portion and the bottom of the stand bead and flexible in response to variation of pressure within the container. The channel portion preferably includes a frusto-conical outer portion extending axially and radially inwardly from the side wall to an annular stand bead and an inner annular frusto-conical portion.

Various emblodiments of the invention will now be described by way of example, and with reference to the accompanying drawings in which: Figure I is a general view of a metal can in one form according to the invention: Figure 2 shows parts of a can in one form according to the invention with a similar can nesting thereon; Figure 3 is a partial side elevation of the body of a can in a second embodiment of the invention, sectioned on a diametral plane; and Figure 4 is a plan view of the embodiment of Figure 3.

Referring to Figures 1 and 2 the can 11 shown therein has a cylindrical body having a relatively thin body wall 12, a bottom 13 substantially thicker than the body wall and integral therewith, a necked shoulder portion 4 at the top of the sidewall, and an easy-opening end 15 which may be opened by pulling upon the tear tab 16 and which is secured to the body by a double seam 15A.

The cans described herein are made from tinplate, which may be continuously annealed or batch annealed to commonly available type. The use of other metals, such as aluminium, is within the scope of the invention. Minor tool modifications may be necessary to take account of the specific mechanical properties of the metal chosen.

In a preferred embodiment of the invention as shown in Figure 2, the can has a body having a cylindrical side-wall 12 of thickness t2 (t2 being less than the thickness t1 of the bottom). The sidewall 12 has a tapered wall portion 12A at its lower end to connect it to the bottom of the can body. The bottom comprises a substantially rigid outer frustoconical wall portion 17 which extends downwardly and inwardly towards the axis of the container to a stand bend 18 which connects the outer frustoconical portion 17 t < ) an inner frustoconical portion 19. The latter is joined integrally to, and surrounds, a flexible panel 20 of the bottom of the can body.The inner frustoconical portion 19 may optionally be capable to slight inward movement in the manner of pivoting about the stand bead as the flexible panel flexes outwardly under the influence of internal pressure in the filled can. the flexible panel 20 is shown as having an outwardly concave annular peripheral bead 13, a planar ring portion 14 surrounded by the bead 13, and a peripheral wall supporting a substantilly flat central, panel portion 16 held in inwardly offset relationship to the planar ring portion 14. It will be seen that the bottom panel portion 16 and bead 13 in Figure 2 do not extend above the level of the top of the outer wall portion 17.The tapered wall portion 12A extends to a height Z above the stand bead 18. and the outer frustoconical portion 17 extends to a height Y above the stand bead 18, while the central panel portion 16 in Figure 2 rises to a height X at the axis. By comparison with the known type of can body discussed above, the arrangament of Figure 2 gives an increased internal volume in a case where all dimensions of the can body outboard of the bottom of the bead 18 are identical in the two can bodies.

lengths and diameters of the side-wall 12 also each being identical. In such a case, to obtain the required pressure containment, the height X is substantially less than the height of the top of the dome in the konwn body.

The following table gives typical dimensions for a tvpical can body according to Figure 2.

(inches) Base thickness t1 0.0118 (Ingoing material) Wall thickness t2 0.0041 Maximum panel height X 0.25 Height to point of departure Y 0.28 from cylindrical outer wall (Start of ironing) Height to start of parallel Z 0.69 wall thickness (End of taper on punch nose) Stacking depth (see below) A 0.12 Nominal stacking clearance B 0.06 (Can base to can top) (see below) In Figure 2, a second can 1 IA, identical to the can 11. is shown stacked upon the can 11.

Its bead portions 18A and outer frustoconical portion 17A are of such dimensions that the stand bead 18 of the channel portion of the can 11A is able to nest within the can end because the outer frustoconical portion 17A is supported by the double seam 15A of the can 11. The depth to which the bottom of the can 11A penetrates the countersink portion of the end 15 is denoted A: and clearance between the bead 18 and the top face of the easy-opening end 15 is denoted B. It will be seen that the easy-opening end 15 has a anti-peaking bead 15B. The clearance B is sufficient to make sure the top can I IA does not touch the centre panel or pull tab of the can end 15 beneath. This nesting arrangement for stacking cans is useful in self-service stores where displays of cans are built up.

Most bulk distribution of cans is by means of pallets which are mechanically loaded and unloaded. The palletising and depalletising equipment commonly used relies on the cans sliding on their bottom beads onto and off laver pads which separate each layer on the pallet. Can bodies such as those described herein permit this form of mechanical handling.

In the embodiment shown in Figures 3 and 4, a can body 21, drawn from a single blank of sheet metal, comprises a cylindrical body wall 22 of thickness t2 and a bottom wall 23 of thickness rl. The thickness t is less than the thickness t. The lower end of the cylindrical wall 22 has a portion 22A which tapers in thickness, if necessary. to join the cylindrical wall 22 to the bottom 23.

The bottom 23 of the body comprises an outer frustoconical portion 27 which extends downwardly and inwardly at an angle D. to join a stand bead 28 upon which the can stands.

The angle D is so chosen as to allow the stand bead 28 to lie within the double seam of a can end seamed on to a similar can body in the manner hereinbefore described so that when stacked, the frustoconical portion 27 of an upper can rests on the double seam of a lower can as in Figure 2. A suitable value for the angle D is of the order of 60 to the horizontal.

An inner frustoconical portion 29 of the bottom extends upwardly and inwardly at an angle E to the horizontal. to join the stand bead'X to a first panel bead 24 which has a substantially arcuate curvature and which is concave outwards. It is advantageous if the angle subtended between the inner and outer frustoconical portions 29 and 27 be sufficiently large for the whole of the divergent internal surfaces of the portions 29 and 27 to receive coating material readily from a spray nozzle directed within the container body. A suitable value for the angle F is of the order of 17 .

The first panel bead 24 is connected by a frustoconical portion 24C of semi-cone angle F (preferably of the order of 20 ) to a second panel bead 25 which is convex outwards. The second bead 25 is connected likewise to a third bead 24A which is concave outwards and connected by a fourth bead 25A to a junction 24B with a flat central panel portion 26. Each of the beads has a similar cross-sectional radius to constitute with the centre panel portion 26 a corrugated. relatively flexible panel within the substantially rigid channel portion 27-29.

While the invention has been described in terms of containers for carbonated beverages and beer, the flexibility of the bottom wall permits the use of cans according to the invention for thermally processed foods. During heating to sterilise the contents of such containers the wall may flex outwardly and during cooling the end wall may retract inwardly.

WHAT WE CLAIM IS: 1. A metal container body having a thin cylindrical side wall closed at one end by a bottom wall thicker than the side wall and integral therewith: the bottom wall including a substantially rigid annular channel portion. upon which the body is capable of standing. and a flexible panel portion: said channel portion having an outer portion. a stand bead and an inner portion: said outer portion extending axially and inwardlv from the cylindrical side wall to the stand bead; and said flexible panel portion including a flat central panel portion surrounded by an upwardly projecting downwardly concave annular bead connecting directly with the inner channel portion; said flexible panel portion being wholly within the axial height of the channel portion as defined between the junction of the cylindrical side vall to outer portion and the bottom of the stand bead and flexible in response to variation of pressure within the container.

2. A container body according to claim 1, wherein the channel portion includes an outer frusto-conical portion extending axially and radially inwardly from the side wall to an annular stand bead upon which the can may stand. and an inner frusto-conical annular portion which extends axially and radially into the body to support the flexible panel portion.

3. A container body according to claim 1 or claim 2, wherein in addition to the annular bead the flexilile panel portion includes a planar ring portion which joins the bead to a peripheral wall supporting the plane central panel portion in inwardly offset relationship to the planar ring.

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

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. In Figure 2, a second can 1 IA, identical to the can 11. is shown stacked upon the can 11. Its bead portions 18A and outer frustoconical portion 17A are of such dimensions that the stand bead 18 of the channel portion of the can 11A is able to nest within the can end because the outer frustoconical portion 17A is supported by the double seam 15A of the can 11. The depth to which the bottom of the can 11A penetrates the countersink portion of the end 15 is denoted A: and clearance between the bead 18 and the top face of the easy-opening end 15 is denoted B. It will be seen that the easy-opening end 15 has a anti-peaking bead 15B. The clearance B is sufficient to make sure the top can I IA does not touch the centre panel or pull tab of the can end 15 beneath. This nesting arrangement for stacking cans is useful in self-service stores where displays of cans are built up. Most bulk distribution of cans is by means of pallets which are mechanically loaded and unloaded. The palletising and depalletising equipment commonly used relies on the cans sliding on their bottom beads onto and off laver pads which separate each layer on the pallet. Can bodies such as those described herein permit this form of mechanical handling. In the embodiment shown in Figures 3 and 4, a can body 21, drawn from a single blank of sheet metal, comprises a cylindrical body wall 22 of thickness t2 and a bottom wall 23 of thickness rl. The thickness t is less than the thickness t. The lower end of the cylindrical wall 22 has a portion 22A which tapers in thickness, if necessary. to join the cylindrical wall 22 to the bottom 23. The bottom 23 of the body comprises an outer frustoconical portion 27 which extends downwardly and inwardly at an angle D. to join a stand bead 28 upon which the can stands. The angle D is so chosen as to allow the stand bead 28 to lie within the double seam of a can end seamed on to a similar can body in the manner hereinbefore described so that when stacked, the frustoconical portion 27 of an upper can rests on the double seam of a lower can as in Figure 2. A suitable value for the angle D is of the order of 60 to the horizontal. An inner frustoconical portion 29 of the bottom extends upwardly and inwardly at an angle E to the horizontal. to join the stand bead'X to a first panel bead 24 which has a substantially arcuate curvature and which is concave outwards. It is advantageous if the angle subtended between the inner and outer frustoconical portions 29 and 27 be sufficiently large for the whole of the divergent internal surfaces of the portions 29 and 27 to receive coating material readily from a spray nozzle directed within the container body. A suitable value for the angle F is of the order of 17 . The first panel bead 24 is connected by a frustoconical portion 24C of semi-cone angle F (preferably of the order of 20 ) to a second panel bead 25 which is convex outwards. The second bead 25 is connected likewise to a third bead 24A which is concave outwards and connected by a fourth bead 25A to a junction 24B with a flat central panel portion 26. Each of the beads has a similar cross-sectional radius to constitute with the centre panel portion 26 a corrugated. relatively flexible panel within the substantially rigid channel portion 27-29. While the invention has been described in terms of containers for carbonated beverages and beer, the flexibility of the bottom wall permits the use of cans according to the invention for thermally processed foods. During heating to sterilise the contents of such containers the wall may flex outwardly and during cooling the end wall may retract inwardly. WHAT WE CLAIM IS:

1. A metal container body having a thin cylindrical side wall closed at one end by a bottom wall thicker than the side wall and integral therewith: the bottom wall including a substantially rigid annular channel portion. upon which the body is capable of standing. and a flexible panel portion: said channel portion having an outer portion. a stand bead and an inner portion: said outer portion extending axially and inwardlv from the cylindrical side wall to the stand bead; and said flexible panel portion including a flat central panel portion surrounded by an upwardly projecting downwardly concave annular bead connecting directly with the inner channel portion; said flexible panel portion being wholly within the axial height of the channel portion as defined between the junction of the cylindrical side vall to outer portion and the bottom of the stand bead and flexible in response to variation of pressure within the container.

2. A container body according to claim 1, wherein the channel portion includes an outer frusto-conical portion extending axially and radially inwardly from the side wall to an annular stand bead upon which the can may stand. and an inner frusto-conical annular portion which extends axially and radially into the body to support the flexible panel portion.

3. A container body according to claim 1 or claim 2, wherein in addition to the annular bead the flexilile panel portion includes a planar ring portion which joins the bead to a peripheral wall supporting the plane central panel portion in inwardly offset relationship to the planar ring.

4. A container body according to claim 1 or claim 2, wherein the can bottom has a

central panel 1 portion which is joined to the channel portion by a plurality ()l successive and concentric flexible annular beads which are alternately downwardly concave and convex.

5. A container body according to claim 4. wherein successive annular beads are joined to one another by a frusto-conical portion of the flexible panel portion.

6. A container body according to claim 5, wherein the or each frusto conical bead-joining portion has a cone angle of substantially 40 .

7. A container body according to any preceding claim having the open end thereof necked in to a diameter smaller than that of the tubular side wall.

8. A container comprising a body according to preceding claim, and an end closure seamed at a seam onto the open of the body, the arrangement being such that the bottom of a like container may rest upon the seam without the annular stand bead touching the end closure within the seam.

9. A container body substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

10. A container body substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawings.