Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to containers having a
fluid-tight sealing means ~or sealing a flexible cover sheet
of impermeable material to an impermeable base or other
structure formed at least partly of rigid or semi-rigid
material and which may be evacuated or pressurised to protect
goods on said base.
It is known, see, for example, ~ritish Patent
Specification ~o.12865~4, to effect a seal between a flexible
envelope and a base of rigid or semi-rigid material by making
use of a flexible inflatable tube along the periphery of
the sheet material which tube is inserted in-to a slot or
groove in the rigid or semi-rigid material and then inflated
into pressure engagement with the walls of the slot or groove.
Such a sealing means finds particular application for
containers where the base is formed of impermeable material
and either air is evacuated from the container so that the
flexible sheet collapses downwardly onto goods to hold them
firmly on the base or in which a gas, for example dry air,
is put into the envelope. ~he inflatable tube along the
periphery of the sheet can be inserted into a groove or slot
extending continuously around the base to effect a fluld-
tight seal between the flexible sheet material and the base.
When such a container is used for long term storage,
it is possible that there may be loss of fluid pressure in
the inflated tube so that the tube is pulled out or partly
pulled out of the slot or groove. ~his problem can arise
particularly if the container is transportable as stresses
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may be applied to the cover when the container is moved. For this reason,
it has- been proposed in the aforementioned Specification No. 1286544 to
provide auxiliary securing means comprising a 1ap on the cover sheet which
is mechanically secured by eyelets engaging hooks on the base of the
container. Such a construction prevents the tube being pulled out of the
groove or slot but does not necessarily ensure that the seal between the
cover sheet and the base remains airtight if pressure is lost in the
inflated tube.
It is an object of the present invention to provide an improved
means for sealing the cover of the container to the base in which the use
of two separate securing means is obviated.
According to this invention, a container comprises a flexible
sheet of impermeable material having a flexible inflatable tube around its
periphery and a rigid or semi-rigid impermeable base member having an
endless slot or groove to receive said tube, the slot or groove being shaped
to hold the tube when the latter is inflated, whereby the tube may be
retained in the slot or groove after insertion therein by inflation of the
tube wherein the tube is provided with resilient means inside the tube and
extending along the whole length of the tube and deformable to permit the
tube being passed into the slot or groove. The resilient means urges the
walls of the tube apart to engage the side walls of the slot or groove and
the resilient means is secured to the inside of the tube leaving a region
between the resilient means and the inside surface of the tube forming a
duct extending continuously along the length of the tube for inflation of
the tube. With this arrangement the tube, when uninflated, has to be
deformed to force it into or out of the slot or groove, thus ensuring a seal
between the base and the cover. The container also has valve means to permit
the interior of the container to be pressurised or evacuated of air.
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With this construction, th0 male member is forced
into -the endless groove or slot and is resiliently retained
therein by the resilience of the elastomeric material of that
member and/or by the resilience of the lining if a lining is
provided in the slot or groove.
In one convenient form of construction, -the male member
comprises an endless tube with resilient means arranged to
~rge at least one wall of the tube ou-twardly against a wall
o* the slot or groove. The tube may be inflatable so that
the cover sheet can be firmly secured and sealed to the base
by inflating the tube. The resilience of the male member
then provides a safeguard against the tube accidentally
being pulled from the slot or groove if this tube is deflated.
In such a construc+ion, conveniently the slot or
groove is formed with rigid walls having ribs, flanges or
other inwardly extending projections engaging the tube. For
example, the slot or groove may have a mouth which is narrower
than the part of the mouth whereby the tube when inflated
cannot be withdrawn through the mouth. Conveniently however
the slot or groove has a longitudinal rib or ribs to grip the
-tube when the latter is inflated. In one construc-tion,
the slot or groove has a waist portion with one or more ribs
extending longitudinally along one or both sides of this
waist portion.
The aforementioned resilient means convenien-tly comprises
a sponge elastomer, e.g. a sponge rubber. Such material
might be put on the outside of the tube but preferably is
inside the tube. If it is inside the tube, the sponge elastomer
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may form a lining not completely filling the cross-section
of the tube so leaving a free passage for inflation of the
tube. Conveniently the sponge elastomer is in the form
of a strip inside the tube and attached to the tube wall
along a narrower edge of the strip; the air space in this
case is between the tube wall and the remaining surfaces
of the strip. In these constructions, when the tube is
inflated, the sponge elastomer is compressed by the fluid
pressure and the tube is firmly retained in the slot or
groove. However the sponge elastomer might completely fill
the tube provided the cells in the sponge are interconnected
to permit passage of air or other fluid along the tube so
-that the tube can be inflated.
The invention furthermore includes within its scope
a contalner comprising a flexible sheet of impermeable
material having a flexible inflatable tube around its periphery
and a rigid or semi-rigid impermeable base member having an
endless slot or groove to receive said tube, the slot or
groove being shaped to hold the tube when the latter is
inflated, whereby the tube may be retained in the slo-t or
groove after insertion therein by inflation of the tube,
wherein the tube is provided with resilient means deformable
to permit the tube being passed into the slot or groove, said
resilient means urging the walls of the tube apart to engage
the side walls of the slot or groove whereby the tube, when
inflated, has to be deformed to force it into or out of the
slot or groove, so ensuring a seal between the base and the
cover, said container furthermore having valve means in the
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base or cover to permit the interior of the container to be
pressurised or evacuated of air.
~he male member need not be an inflatable tube; it
may be a solid member which is a force fit in the slot or
groove. In this case, preferably said endless male member
is formed of elastomeric material shaped with ridges or
projections on at least one of the surfaces facing a wall
of the slot or groove. Preferably also with such a
construction, the walls of said slot or groove are lined with
a resilient material which is softer than the material of
~the male member.
In one form of construction, the male member has ribs
or projeotions extending longitudinally along one or both of
its side faces. Such ribs or projections might be formed as
rounded beads or pointed or cusp-shaped projections.
In one convenient form of construction the projections are
wedge-shaped projections, the wedge shapes being sùch as to
facilltate entry of the male member into the groove but
having shoulders which resist withdrawal of the male member
from the groove engaging into the soft lining of the groove.
Preferably the male member is shaped -to have a
rib or ribs or other projection which extends outwardly
from the outer wall of the envelope beyond the outer edge
of the outer wall of the groove when the male member is
inserted in the groove. ~uch a rib or other projection
facilitates man~al gripping of the male member to force
it into the groove when sealing the container and to remove
it therefrom when unsealing the container.
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The male member conveniently is formed of a
rslatively hard plastics material. This me~ber may be formed
integrally with -the cover or may be secured thereto~ e.g.
by welding or by an adhesive or it may be separate from the
cover; in the last-mentioned case, the peripheral portion
of the cover is put into the groove and the male member then
forced into the groove to wedge the cover therein.
~he aforementioned lining of -the groove is preferably
of a soft resilient material for example rubber, which is
softer than the male member. ~his lining material may
have outwardly-turned portions or enlarged ends extending over
the tops of the side walls of the groove.
The invention further includes within its scope a
container comprising an impermeable base and a flexible
impermeable cover, the base having a load-carrying surface
with a continuous groove e~tending around that surface or at
least the major part thereof, said groove comprising two
spaced upright wall members sealed to or integral with the
base and the cover having around its periphery or attached to
its peripherv an endless male member for inserting into said
groove, which male member is formed of elastomeric materia~
and shaped to be a force fit into said groove between said
upright walls or between linings on said walls, to seal the
cover to the base, valve means being provided in the base or
cover to permlt the interior of the container to be
pressurised or evacuated of air. Preferably the walls of the
groove, on their inwardly-facing surfaces, are lined with
a resilient material which is softer than the material of
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said male member.
The aforementioned base is conveniently formed of
metal but may be made of other materials. Preferably
it is formed as a pallet. Such a palle~t may be shaped in
the known way for admission of the forks of a fork-lift truck
underneath the impermeable base to enable the container
to be lifted. The groove may be formed around the peripheral
edge of the pallet or may be spaced, over the whole or part
of its length, inwardly from~the periphery of the base. This
latter arrangement facilitates for example the fitting of
posts on the base for the supporting of one pallet on top of
ano-ther.
The following is a description of a number of
embodiments of the invention, reference being made to the
accompanying drawings in which:-
~igure 1 is a diagram showing, in elevation~ a
- container of the type to which the present invention can be
applied;
Figure 2 is a sectional perspective view of part of
a sealing means for a container and illustrating one
embodiment of the invention; P
Figure 3 is a diagrammatic exploded sectional perspective
view of part of another cons-truction of sealing means;
Figure 4 shows the sealing means of Figure 3 assembled
together to make a seal;
Figu-res 5 and 6 are views similar to Figures 3 and 4
of.yet a further construction of sealing means;
~igure 7 is an e~ploded perspective view of part of a
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base and cover (in section) for fo~;ming another construction
of container;
Figure 8 is a view similar to ~igure 7 of another
embodimen-t of the invention;
Figures 9 and 10 illustrate further forms of ribs
on the male member; and
Figure 11 illustrates the provision of ribs on a
lining of a groove in another construction.
Referring to ~igure 1, there is shown diagrammatically
a container for goods comprising a rigid impermeable base 1
constructed as a pallet with openings 2 for the forks of a
fork-lift truck. Near the periphery of the base is an
upstanding ~ember 3 -forming an endless groove (not shown)
in which is secured the periphery of a flexible impermeable
cover sheet 5, which is typically formed of butyl rubber.
Valve means 6 are provided in the base 1, or alternatively in
the cover 5 enabling air to be partially evacuated from within
the container so that the cover sheet is drawn down onto goods
7 within the container. Only a small reduction in air
pressure is necessary to ensure that the cover is pressed, by
the outside atmospheric pressure, into tight engagement wi~h
goods on the base. The goods are thus firmly held on the
base. The valve means may alternatively or additionally be
arranged for pressurising the container, e,g. with dry air
or with an inert gas as may be desired in some cases for
storing goods.
The present invention is concerned more particularly
with the manner of sealing the cover 5 to the base 1 and
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Figure 2 illustrates one construction for this sealing means.
Referring to Figure 2 of the drawingS there is shown
a rigid impermeable base pla-te 10 which may constitute the
top surface of pallet 1. ~-ttached to this base plate
around the periphery thereof is a member 11 of rigid or semi
rigid material, for example plastics material, having a slot
therein which is open at the bottom except for narrow cross-
ties as indicated at 12. The mouth of the slot as shown at
13 is narrower than the part i4 of the slo' inwardly of the
mouth. The edge of a flexible cover sheet 15 around its
whole periphery has an integral tube 16 which can be passed
through the mouth 13 of the slot and then inflated into pressure-,
sealing engagement with the walls of the slot by means of an
inlet valve not shown. Wi-thin the tube 16 is a resilient
lining 17 of sponge elastomeric material, e.g. sponge rubber,
which normally pushes the sides of the tube outwardly so that,
even if the tube is not inflated, it engages the walls o-f the
slot. This resilient lining 17 extends along the whole
length of the tube. On inflation of the tube, the sponge
material is compressed and the tube is firmly held by the slot.
In Figures 3 and 4 another construction is shown, Figure
3 illustrating the periphery of the cover and the groove in
the base before they have been put together and Figure 4
showing the two parts of Figure 3 in the assembled position.
Referring to Figures 3 and 4, there is shown a groove 19
formed of sheet metal, one side wall 20 of a groove 19 being
curved, in transverse section, to form a waist 22 in the groove
19. The other side wall 23 is substantially straight but has
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two longitudinal ribs 24 in the waist 22 of the groove. ~he
sheet 25 of flexible plastics material to be secured in
position has an integral tube 26 along its periphery, one
side of the tube being filled with sponge elastomer 27. As
seen in Figure 4, the tube has to be squeezed to deform the
sponge material 27 so as to permit insertion in the groove.
It is thus retained therein resiliently even without
inflation. Inflation of the tube ensures a firm grip, the
air pressure compressing the elastomer~
~igures 5 and 6 are views similar to ~igures 3 and 4
but showing a modified construction. These figures show a
construction in which an upstanding groove or channel 30
having a waist portion 31 is formed by two side walls ~2, 33.
The wall 33 may have longitudinal ribs as shown at 35. A
sheet 36 of flexible plastics material has an integral tube
37 along its periphery for insertion in the groove. The
tube 37 is of elongate internal form in cross-section and has
a strip 38 of sponge elastomer attached by one of its
narrower edges to one of the narrower internal faces of the
tube so leaving air spaces 39, 40 between the two broader
faces of the strip and the -tube wall. The tube is inserted
in the groove 30 and is resiliently retained thereln by the
elastomer strip 38. Inflation of the tube ensures that
it is firmly held in position. Figures 5 and 6 also
illustrate the provision of an integral flap 41 on the sheet
36 which fits over one side wall of the groove or channel
30 forming a lip to improve the sealing.
Referring to Figure 7, there is shown part of a metal
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tray ha~ing an impermeable base 50 with two upright walls
51, 52 which define an endless groove 53 around the
periphery of the base. The tray is conveniently constructed
as a pallet, for example, with transverse members on its
underside to enable the forks of a for~-lift truck to be
inserted under the base 50 when the tray is resting on the
ground. In the embodiment of ~igure 7, -the groove is lined
on both sides with soft rubber 54, this soft rubber extending
over the top edges of the walls 11, 12 as shown at 55.
For storing goods on the tray, a flexible cover, part
of which is shown a-t 56, which is formed of impermeable
material is put over the goods and an endless male member
57, secured on the periphery of the cover and extending
a~ound the periphery thereof is forced into the groove 53
between the linings 54. The male member 579 in cross-section
is tapered so that the thickness decreases towards its lower
edge. In the embodiment illustrated, one face is formed
with a series of wedge-shaped ribs 58 extending along the
length of the male member, each rib having an upper shoulder 59
which engages in the sof-t rubber lining 54 to ensure that the
male member 57 is held firmly in the groove. This male
member 57 is formed of a resilient plastics material,
preferably a harder material than the lining 54 and has an
integral outwardly directed flange 60 which, when the member
57 is forced into the groove 53, extends outwardly over the
top of the lining material 55 above the top of the outer
wall 51. The flange 60 facilitates manual forcing of the
- male member into the groove when the container is to be
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sealed and withdrawal therefrom when the container is to be
unsealed. The lower end of the male member engages the soft
lining material at the bot-tom of the groove 53, the flange 60
engages the top of the lining and the side faces of the male
member engage the inwardly-facing surfaces of the lining to
give an airtight seal~
When the male member 57 has been inserted into the
groove 53, air is partially evacuated from the region within.
the cover 55 through a valve (not shown) in the cover or,
preferably, in the base. The vacuum holds the cover down
onto any goods on the base so securing such goods firmly, as
may be necessary for transport purposes.
~igure 8 shows another construction in which the
endless groove, shown at 61, is formed of a metal or ceramic
member 62 with a smooth finish and secured around the periphery
of a pallet 63. The male member, shown at 64 with longitudinally-
extending ribs 65 and an outwardly-directed flange 66, is
forced into the groove 60 to be gripped by compression of the
resilient material. A cover of flexible impermeable material
68 is welded or otherwise secured to the male member 64 to
form, with the pallet 63, a container which can be partially
evacuated as described above.
Figures 9 and 10 illustrate at 75 and 76 respectively,
alternative rib shapes for use on the ma.e member. As shown
at 77 in ~igure 11, the lining 78 of a groove may also be
provided with longitudinally extending ribs. Other rib
shapes may be used on the lining, for example ribs of the
shape shown in ~igures 9 and 10.
13.
