GB2103538A

GB2103538A - Making drums for packaging

Info

Publication number: GB2103538A
Application number: GB08217392A
Authority: GB
Inventors: Rudolf Ruefenacht
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1981-06-18
Filing date: 1982-06-16
Publication date: 1983-02-23

Abstract

Drums for holding detergent powder are manufactured from board by a hot forming process in which a blank is heated, wrapped round a mandrel to form a sleeve and fitted with a base, the characteristic of the drum produced being that its sleeve is formed to correspond to the shape of the mandrel which is of substantially rectangular cross-section and has a longer pair of convex faces. <IMAGE>

Description

SPECIFICATION Drums for detergent powder and a process for manufacturing them This invention relates to drums suitable for holding detergent powder.

A few years ago, the representative bodies of the European detergents industry agreed that detergent powder would generally be sold to the consumer in packs of standard sizes, rather than in packs of a size chosen by the individual manufacturer as hitherto. Since that decision was taken, some of the larger sizes agreed upon, notably the E5, E10 and E15 sizes have become quite popular. The E10 and E15 sizes are relatively large for a housewife to handle, and it quickly became the practice in the trade to form these sizes not as folded cartons but as drums fitted with a carrying strap.

The first drums were circular in cross-section. These were generally satisfactory and were certainly easy to manufacture, since they could be formed by a spiral winding process.

However, it was subsequently suggested that drums of essentially rectangular cross-section would be an improvement over circular ones, since they would be less unwieldy to carry, they would stack more conveniently, and the surfaces of the drum would be more suitable for bearing printed matter concerning the contents. A number of our European companies have now adopted such a drum.

it is more difficult to manufacture drums of rectangular cross-section using a spiral winding process, and we have found it more convenient to use a process of hot-forming a rectangular blank round a mandrel. A base blank is glued into place once the sleeve portion of the drum has been formed.

We are still not entirely satisfied with these drums however. In the first place, rectangular drums are not as strong as circular ones. This necessitates the use of a heavier grade of board and since the usual weight of board (700g/m2) is close to the limit which top quality printing machinery can accept, to be forced to use heavier board can be disadvantageous. Secondly, although the wide area of the face of a rectangular drum is advantageous, it is also more prone to scuffing during transit than is a circular drum. Thirdly, because of the relative weakness of the face of a rectangular drum, it is less able than a circular one to resist outwards deformation during glueing in the base blank and, consequently, some glueing difficulties have been experienced.

We believe that the difficuities enumerated above can be alleviated if the drum is formed not into a rectangular cross-section but into a cross-section which is substantially rectangular but in which the two longer faces are slightly convex.

Accordingly, the present invention provdes a process for forming a drum from a substantially unscored rectangular blank which comprises the steps of (i) heating the blank; (ii) simultaneously or subsequently deforming the blank by wrapping it round a mandrel so that one end of the blank overlaps the other; (iii) joining the two ends of the blank to form a sleeve; and (iv) inserting a base member into the sleeve to form a drum, characterised in that the mandrel has a crosssection which is substantially rectangular, the longer pair of faces being convex.

We are aware of Swiss Patent No 530902 which relates to a method of making cartons or drums of any desired cross-section by using a blank which is scored over its entire surface with narrowly spaced continuous lines to aid folding. However, such blanks inevitably produce drums or cartons whose surface is scored, which is extremely disadvantageous as regards the application of printed matter. Our invention in contrast can be applied to blanks which are completely unscored, or which bear only minimal scoring where it is intended the four corners of the resultant drum should appear.

The invention will be further illustrated with reference to the accompanying drawings in which Figure 1 is a flow sheet of a process in accordance with the invention, and Figure 2 is a cross-section on the line A-A of Fig. 1 of a mandrel suitable for performing the process.

The general arrangement of the process, as performed in the manner shown schematically in Fig. 1, is that flat, substantially unscored cardboard blanks (10) are fed to the apparatus which consists of a number of operating stations located adjacent the same number of mandrels, and drums (11) having the required cross-section, fitted with a glued and curled base are removed from it. The mechanism for feeding and removal is not shown. Each individual blank is fed to a mandrel (12) shown in plan, the cross-section of the mandrel, on the line A-A of Fig. 1 being shown in Fig. 2.

In more detail, flat blanks are fed to operating station S1, and preformed by wrapping first one corner of the blank, then another round a mandrel at stations S2 and S3. Glue is applied to the blank between stations S3 and S4, and at S4 the sleeve portion of the drum is preformed by wrapping the blank completely round a mandrel. At station S5, the preformed sleeve is pushed onto the first mandrel of a twelve-headed rotating system comprising a rotatable carrier (13)which rotates each blank on its mandrel to an operating station (14). When one operation has been performed, the mandrel and its accom panying blank are rotated with the carrier to the next station.At station S6 the two ends of the blank which have been glued to form a side-seam are pressed to consolidate the bonding and at S7 the outer end of the sleeve is glued on the inside to receive the base blank. The pressing is continued at stations S8 and S9 and at S10 a base blank (15), which has been pre-folded so that its edges are upstanding at right angles, is pushed into the fully formed sleeve. At stations S11, S12 and S14 the base seam is curled in three stages, the sections which are achieved at each station being shown. Finally, at station 514 drums are removed from the rotating system. They then go on to top curling, riveting, filling, topping and taping machinery which will not be described.

Apparatus suitable for use in a process such as that described above is availabie from Goring of W. Germany.

We have found that drums of the crosssection illustrated are practical and convenient for the consumer. We consider that they are less prone to base glueing difficulties than are rectangular drums and we also consider that they can be made more satisfactory in lighter quality boards than can rectangular drums.

Claims

1. A process for forming a drum from a substantially unscored rectangular blank which comprises the steps of: (i) heating the blank; (ii) simultaneously or subsequently deforming the blank by wrapping it round a mandrel so that one end of the blank overlaps the other; (iii) joining the two ends of the blank to form a sleeve and (iv) inserting a base member into the sleeve to form a drum; characterised in that the mandrel has a crosssection which is substantially rectangular, the long pair of faces being convex.