[0001] This invention relates to containers made of cardboard, corrugated board or similar
lightweight semi-rigid sheet material, of the kind having a tubular body formed by
a row of hingedly interconnected wall panels joined end to end by a connecting strip
which is contiguous with one of the end panels of the row and is secured, usually
by gluing, to the panel at the other end. This join between the end panels of the
row to make the tubular body is known as "the manufacturer's joint". The container
is closed by suitable arrays of end closure flaps hinged to opposite ends of the respective
wall panels and foldable inwardly to close the ends of the tubular body.
[0002] Such a container has a number of corners, each defined at the meeting point of three
hinge lines, namely the hinge line between two adjacent wall panels and the hinge
lines between those wall panels and their associated closure flaps. The latter flaps
are of course separate from each other at such corners, and this can cause a problem
if it is desired to make the made up container dust-tight and/or light-tight to a
degree, because dust or light can find its way through the separations between the
end closure flaps in the corners of the container. This problem is particularly noticeable
at those corners which are located at the respective ends of the manufacturer's joint
previously referred to, because the aforementioned connecting strip constitutes an
extra thickness of board which further separates the mutually adjacent regions of
the closure flaps at the joint.
[0003] Viewed from one aspect the present invention provides a blank made of cardboard,
corrugated board or similar lightweight semi-rigid sheet material, for making a container
incorporating a manufacturer's joint as herein defined, wherein at least one sealing
part is provided in the blank, arranged so as to be located in the region of at least
one end of the manufacturer's joint in the made up container, and arranged to be incorporated
in sealing fashion in the relevant corner of the made up container inside of the said
closure flaps at said corner.
[0004] Such sealing part or parts will be arranged to underlie and thereby effectively close
any gap that would otherwise be present between the edges of the respective closure
flaps adjacent the corner.
[0005] Such a sealing part could be provided at only one end of the manufacturer's joint,
so as to provide an enhanced seal at only one corner of the made up container. Such
an arrangement may be useful for example if the container is to be kept one way up,
with the sealed corner at the top. Preferably however at least two said sealing parts
are provided, arranged to be located one at each end of the manufacturer's joint.
[0006] The said sealing parts may be provided on any convenient part of the blank adjacent
the ends of the manufacturer's joint, for example on the said connecting strip, and/or
on one or other of the end closure flaps at the relevant corner, and/or on a combination
of such elements by spanning between them. Preferably however the said sealing parts
are provided on the said connecting strip, one at each end thereof. The sealing parts
are preferably hingedly connected to the said connecting strip, although this is not
essential as they could be manually folded relative to the strip during erection of
the container.
[0007] It is normal for the adjacent edges of each adjoining pair of end closure flaps to
be at least slightly laterally spaced away from each other adjacent the relevant corner
to enable them to be folded in without interfering with each other at the corner,
or in other words to allow for the thickness of the board upon such folding in. However,
despite the advantage of such an arrangement in permitting the flaps to be folded
in a tidy fashion, it has the disadvantage of exacerbating the problem, already referred
to, of making the corners of the container dust-tight and/or light-tight to a degree.
In a preferred form of the invention, therefore the said closure flaps at the said
relevant corners are not laterally spaced apart at their adjoining edges adjacent
the said corners.
[0008] Preferably the last mentioned feature is also applied to the other adjacent pairs
of closure flaps of the blank, i.e. those not forming part of the corners at the ends
of the manufacturer's joint. Thus in a preferred form of the invention all of the
adjacent pairs of closure flaps are not laterally spaced apart at their adjoining
edges adjacent what will be the corners of the made up container.
[0009] An embodiment of the invention will now be described by way of example and with reference
to the accompanying drawings, in which:
Figure 1 is a plan view of a blank made of double faced corrugated board, according
to the invention;
Figures 2 to 6 are enlarged fragmentary views of the corner regions of the blank indicated
by the reference letters A to E respectively in Figure 1;
Figure 7 is a fragmentary perspective view of the inside of the corner B of the made
up container;
Figure 8 is a similar view of the inside of the corner F as indicated in Figure 1;
Figures 9 and 10 are fragmentary perspective views showing successive stages in the
erection of the container in the corner E thereof; and
Figures 11 and 12 are similar views relating to corner D.
[0010] Referring first to Figure 1, a blank for forming a four-sided box-like container
according to the invention comprises a row of four hingedly interconnected side wall
panels 1 to 4, with a connecting strip 5 hinged to the panel 4 and intended to be
glued to the edge of the panel 1 in the conventional manner referred to as the manufacturer's
joint, to form the four-sided tubular body of the container. Arrays of bottom end
closure flaps 6 to 9 and top end closure flaps 10 to 13 are hinged to the ends of
the respective wall panels.
[0011] Referring now to Figures 2 to 4, at each of the corner regions A to C the two end
closure flaps are only separated by a cut 14 adjacent the corner, rather than being
spaced apart by a narrow slot as is conventional. The same is the case at the corners
F to H in Figure 1.
[0012] Figure 7 shows the bottom corner region B of the erected container, on the inside
looking down. Bottom closure flap 7 is folded in first, followed to flap 8. As a result
of there only being a cut 14 between the closure flaps, rather than a slot, the region
15 of flap 7 adjacent the cut is crushed into the angle between wall panel 3 and flap
8, so as to enhance the dust-tightness and light-tightness of the corner. The effect
at corners A and C is similar.
[0013] Figure 8 shows the top corner region F of the erected container, on the inside looking
up. The closure flap 11 is folded in first, then the closure flap 10. The region 16
of the flap 11 is crushed into the angle between the wall panel 1 and the closure
flap 10, with the same effect as described above. Similar effects are achieved at
top corners G and H.
[0014] Referring now to Figures 5 and 6, sealing parts in the form of small triangular extensions
16 are hingedly connected to the respective ends of the connecting strip 5, separated
from the adjoining closure flaps 9 and 13 by cuts 17.
[0015] Figures 9 and 10 show how top corner D is erected, from the inside looking up. Top
closure flap 10 is folded in first, followed by closure flap 13. As flap 10 is folded
in, it pushes extension 16 down about its hinge line so that the extension becomes
incorporated in the erected corner, inside of the closure flaps, to enhance the dust-tightness
and light-tightness of the corner. The same effect is achieved at bottom corner E
as illustrated in Figures 11 and 12. Here, bottom closure flap 6 is folded in first,
followed by flap 9. Also, at corner D, region 18 of top closure flap 10 is crushed
into the angle between wall panel 4 and flap 13, to further enhance the seal.
1. A blank made of cardboard, corrugated board or similar lightweight semi-rigid sheet
material, for making a container incorporating a manufacturer's joint as herein defined,
wherein at least one sealing part is provided in the blank, arranged so as to be located
in the region of at least one end of the manufacturer's joint in the made up container,
and arranged to be incorporated in sealing fashion in the relevant corner of the made
up container inside of the said closure flaps at said corner.
2. A blank as claimed in claim 1, wherein at least two said sealing parts are provided,
arranged to be located one at each end of the manufacturer's joint.
3. A blank as claimed in claim 2, wherein the said sealing parts are provided on the
said connecting strip, one at each end thereof.
4. A blank as claimed in claim 3, wherein the said sealing parts are hingedly connected
to the said connecting strip.
5. A blank as claimed in any preceding claim, wherein the said closure flaps at at least
one of the said relevant corners are not laterally spaced apart at their adjoining
edges adjacent the said corners.
6. A blank as claimed in any of claims 1 to 4, wherein all of the adjacent pairs of closure
flaps are not laterally spaced apart at their adjoining edges adjacent what will be
the corners of the made up container.
7. A blank as claimed in claim 1, substantially as hereinbefore described with reference
to Figure 1 of the accompanying drawings.
8. A container made from a blank as claimed in any of claims 1 to 5.