GB1589336A - Bottom end for a packaging container - Google Patents

Description

(54) A BOTTOM END FOR A PACKAGING CONTAINER (71) We, SCHMALBACH LUBECA GmbH, of 1, Schmalbachstrasse, D-3300 Braunschweig, Federal Republic of Germany; a German body corporate, 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: The present invention relates to a bottom end for packaging containers, more especially for large tin cans, buckets or the like, preferably of non-circular cross-sectional shape, made of sheet metal which is connected by flanging in known manner to the body of the container.

Plain or only arcuate bottom ends for packaging containers have not been found sufficiently reliable in connection with the stresses occurring during transportation or storage of containers especially when such are stacked.

Known bottom ends readily develop vibration cracks and deformations on account of external influences which results in the seal between body and bottom end being suspect. As a consequence of the aforesaid considerations it has been necessary to use relatively thick material for the bottom ends of such containers or at least to use material for the bottom ends which is thicker than the material of the body so as to obtain the sufficient strength therefor.

The desire to obtain a reduction of the thickness of the material of the bottom end so as to reduce the costs of such containers led to the development of special profiles for the bottom end in order thereby to obtain its stability and resistance. The application of concentric beads to the bottom end whilst providing certain advantages did not, in connection with externally occurring stresses, prevent with sufficient reliability any instability of the bottom end during transportation and storage. The reduced material thickness of these bottom ends so formed moreover showed a subsceptibility to bending resulting in difficulties during connection by automatic means of the bottom end to the container body. It is an object of the invention to avoid or minimise the aforesaid disadvantages of the mentioned bottom ends to provide an improved bottom end.Further it is an object to provide a bottom end which has such a high resistance to vibrations and transportation, more especially whilst avoiding vibration cracks, that the overall strength thereof is considerably improved and wherein denting and crinkling is reduced or is so effectively absorbed to substantially prevent or minimise any leakage of the bottom end and body join. Moreover, even with a small overall height the bottom end may be made sufficiently bend-resistant and flat in order to prevent interferences during the joining of the bottom end to the body.

According to the present invention there is provided a bottom end of sheet metal for a packaging container made of sheet metal and connectable by flanging in known manner to the body of the container, comprising an edge flange extending substantially at right angles to the central axis of the bottom end and adjoined by a chuck wall inclined thereto and radially inwards thereof and extending towards the central axis of the bottom end and merging via a transition portion into an undulating section extending radially inwards at right angles to said central axis, said undulating section merging via a curved arc portion into a flat central portion of the bottom end which is located adjacent the plane in which the edge flange lies and in a region between the medial plane of the undulations and the plane of the flange.

The bottom end according to the invention besides an extremely good resistance to bending also has an excellent overall strength. The wavy or undulating section permits pressure stresses to be effectively absorbed without leaks forming in the critical region, namely the region of flanging of body with the bottom end.

The inclined wall permits the stacking of identical bottom ends one above the other without jamming which advantageously permits the automatic sealing operation of the container body to the bottom end to be effected without interference. The transition of the wavy or undulating section towards the bottom end portion surface, via an outwardly curved arc provides the bottom end with a resilience which ensures that a consumer is able to extract any residues of the container filling. The curved arc portion extends only in a direction away from the plane in which the undulations lie.

In accordance with a further feature of the invention the plane of the central portion is located spaced from the plane of the edge flange in the direction of the undulating portion.

According to a further feature of the innovation, the wavy section has a height of undulation substantially corresponding to 0.257 times the overall height of the bottom end.

The invention will be described further, by way of example, with reference to the accompanying drawing which is half a cross-sectional view on enlarged scale of a packaging container bottom end.

A bottom end 1 is shown in the drawing formed of thin metal sheet and having an edge flange 4 extending substantially at right angles to the central axis of the bottom end 1 with the free edge 5 thereof being bent upwardly for the purposes of eliminating injuries which might be caused in subsequent handling of the bottom end 1. The edge flange 4 of the bottom end 1 serves for providing a connection 2 by seamins with the container body 3 as indicated in broken lines.

An inclined chuck wall 6 adjoins the edge flange 4 radially inward thereof and on one side faces the centre of the bottom end and leads into a transition portion 7. The portion 7 forms the starting region for a wavy or undulating section 8 extending radially inwards at right angles to the base axis and which, via an outwardly curved convex arc portion 9 terminates in or runs into a predominantly flat central bottom end portion 10.

It is clearly shown in the drawing that the plane of the central portion 10 is located slightly within or upwardly of the plane of the edge flange 4. This avoids the central portion 10 of the bottom end making contact with the supporting plane for the bottom end during the positioning of the container for the flanging 2.

The undulating section 8 expediently has an undulation height h which corresponds to about 0.257 times the height T of the chuck wall.

As already stated the bottom end so formed has optimal overall strength resistance to external stresses and resistance to warping. It thus fully conforms to safety requirements for transporting. The resistance to bending facilitates the automatic connecting process with the body 3 of the container, and the sealing process may be further mechanised as a result of the mutual slackability of the bottom ends as permitted by the inclined wall 6.

Finally, the substantially dome-shaped configuration formed by the central bottom end portion 10 with the arc portion 9, a consumer may readily remove any residual charge material since the residual material forcibly collects in this region.

The invention is preferably applicable to bottom ends which are non-circular in plan although is not restricted to such non-circular bottom ends or containers and certain sizes of tubs, large tin cans or the like containers may, moreover, also be employed with advantage in barrels of cylindrical or other cross-sectional shape.

WHAT WE CLAIM IS: 1. A bottom end of sheet metal for a packaging container made of sheet metal and connectable by flanging in known manner to the body of the container, comprising an edge flange extending substantially at right angles to the central axis of the bottom end and adjoined by a chuck wall inclined thereto and radially inwards thereof and extending towards the central axis of the bottom end and merging via a transition portion into an undulating section extending radially inwards at right angles to said central axis, said undulating section merging via a curved arc portion into a flat central portion of the bottom end which is located adjacent the plane in which the edge flange lies and in a region between the medial plane of the undulations and the plane of the flange.

2. A bottom end as claimed in claim 1, in which the curved arc portion extends only in a direction away from the plane in which the undulations lie and merges with the flat central portion.

3. A bottom end as claimed in claim 1 or 2, in which the undulation section has an undulation height which substantially corresponds to 0.257 times the height (T) of the chuck wall.

4. A bottom end for a packaging container substantially as herein described with reference to and as illustrated in the accompanying drawing.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. located spaced from the plane of the edge flange in the direction of the undulating portion. According to a further feature of the innovation, the wavy section has a height of undulation substantially corresponding to 0.257 times the overall height of the bottom end. The invention will be described further, by way of example, with reference to the accompanying drawing which is half a cross-sectional view on enlarged scale of a packaging container bottom end. A bottom end 1 is shown in the drawing formed of thin metal sheet and having an edge flange 4 extending substantially at right angles to the central axis of the bottom end 1 with the free edge 5 thereof being bent upwardly for the purposes of eliminating injuries which might be caused in subsequent handling of the bottom end 1. The edge flange 4 of the bottom end 1 serves for providing a connection 2 by seamins with the container body 3 as indicated in broken lines. An inclined chuck wall 6 adjoins the edge flange 4 radially inward thereof and on one side faces the centre of the bottom end and leads into a transition portion 7. The portion 7 forms the starting region for a wavy or undulating section 8 extending radially inwards at right angles to the base axis and which, via an outwardly curved convex arc portion 9 terminates in or runs into a predominantly flat central bottom end portion 10. It is clearly shown in the drawing that the plane of the central portion 10 is located slightly within or upwardly of the plane of the edge flange 4. This avoids the central portion 10 of the bottom end making contact with the supporting plane for the bottom end during the positioning of the container for the flanging 2. The undulating section 8 expediently has an undulation height h which corresponds to about 0.257 times the height T of the chuck wall. As already stated the bottom end so formed has optimal overall strength resistance to external stresses and resistance to warping. It thus fully conforms to safety requirements for transporting. The resistance to bending facilitates the automatic connecting process with the body 3 of the container, and the sealing process may be further mechanised as a result of the mutual slackability of the bottom ends as permitted by the inclined wall 6. Finally, the substantially dome-shaped configuration formed by the central bottom end portion 10 with the arc portion 9, a consumer may readily remove any residual charge material since the residual material forcibly collects in this region. The invention is preferably applicable to bottom ends which are non-circular in plan although is not restricted to such non-circular bottom ends or containers and certain sizes of tubs, large tin cans or the like containers may, moreover, also be employed with advantage in barrels of cylindrical or other cross-sectional shape. WHAT WE CLAIM IS:

1. A bottom end of sheet metal for a packaging container made of sheet metal and connectable by flanging in known manner to the body of the container, comprising an edge flange extending substantially at right angles to the central axis of the bottom end and adjoined by a chuck wall inclined thereto and radially inwards thereof and extending towards the central axis of the bottom end and merging via a transition portion into an undulating section extending radially inwards at right angles to said central axis, said undulating section merging via a curved arc portion into a flat central portion of the bottom end which is located adjacent the plane in which the edge flange lies and in a region between the medial plane of the undulations and the plane of the flange.

2. A bottom end as claimed in claim 1, in which the curved arc portion extends only in a direction away from the plane in which the undulations lie and merges with the flat central portion.

3. A bottom end as claimed in claim 1 or 2, in which the undulation section has an undulation height which substantially corresponds to 0.257 times the height (T) of the chuck wall.

4. A bottom end for a packaging container substantially as herein described with reference to and as illustrated in the accompanying drawing.