Note: Descriptions are shown in the official language in which they were submitted.
: .
his invention relates to containers having a fluid-
tight sealing means for sealing a flexible cover sheet of
impermeable material to an impermeable base or other structure
formed at least partly rigid or semi-rigid material and
which may be evacuated or pressurised to protect goods on
said base.
Containers of this type are known, for example, from
British Patent No. 1, 191,921 and U.S. Patents Nos. 3,850,214;
3,815,650 and 3,929,178. It is known, see, for example,
Specification No. 3,850,214 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 into 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 drom the container so that the ~lexible :.
sheet collapses downwardly onto goods to hold them firmly
20 on the base or in which a gas, for example dry air, is put :
into the envelope. The inElatable tube along the periphery
of the sheet can be inserted into a groove or slot extending
continuously around the base to ef~ect a fluid-tight seal
between the flexible sheet material and the base.
When such a container is used for lon~ 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. This problem can arise
. . : . . . ,, . . ,, . . .. , . :, :.~ .. . . . : : . :
` particularly if the container is trans.portahle as. stres.ses may be applied
to the cover when the container is moved. For this reason, it has been
proposed in the aforementioned Specification No. 3,850,214 to provide
auxiliary securing means comprising a flap on the cover sheet which is
mechanically secured by eyelets engaging hoods 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
cover sheet of i~permeable material and an impermeable base, the base
having a load-carrying surface with an endless channel extending around at
least a major part of that surface, said channel comprising two spaced
upright walls on the base, and the cover sheet having, around its periphery,
an endless male member for inserting into said channel, said male member
being formed at least partly of elastomeric material and being wedge-shaped
in section to be a force fit into said channel between said upright walls
so as to orm an airtight seal between the cover sheet and the base and
wherein valve means are provided to
-- 3 --
. . .
: :
.: .
,, . '
-' .: ,
: . . . .
' : :
6~
permit 'he in~e:^ior c~ ihe container to be pressurised or
evacuated of air.
With this construction, the 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.
The male member 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 ri.bs
or projections extending longitudinally along one or both
o~ 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 such as to
facilitate entry of the male member into the groove but
having shoulders which resist withdrawal of the male member
Erom the groove engaging into the soEt 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 i.s inserted in the
4. ~:
,. : , . :, ;
- ~ .. . . . ..
.
- , :: '.'.' ,, . : , : ~ . :
',
groove. Such a rlb~ o~her projection facilitates manual
gripping of the maie member to force it into the groove when
sealing -the container and to remove it therefrom when unsealing
the container.
The male member conveniently is formed of a relatively
hard plastics material. This member 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 ~rom the cover; in the
last-mentioned case, the peripheral portion of the cover is
10 put into the groove and the male member then forced into the
groove to wedge the cover therein.
The aforementioned lining of the groove is preferably
of a soft resilient material for example rubber, which is
softer than the male member. This lining material may have
15 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
20 with a continuous groove extending around that surface or at
least the major part thereof, said groove comprising two
spaced upright wall members sealed to or :lntegral with the
base and -the cover having around its periphery or attached to
its periphery an endless male member ~or :lnsertiny :lnto sa:ld
25 yroove, which maIe member is Eormed oE elastomeric material
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 permit 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
said male member.
The aforementioned base is conveniently formed of metal
but may be made of other materials. Preferably it is formed
as a pall~t. Such a pallet may be shaped in the known way
for ad~ission of the forks of a fork lift truck underneath
the impermeable base to enable the container to be liEted.
~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 another.
The following is a description of a number of
embodiments of the invention, reference being made to the
accompanying drawings in which:-
Figure 1 is a diagram showing, in elevation,a container
of the type to which the present invention can be applied;
Figure 2 is an exploded perspective view of part of a
base and cover (in section) for forming one construc-tion
of container;
F:lgure 3 is a view similar to Figure 2 of another
embodiment of the invention;
2.5 Figures 4 and 5 illustrate further forms of ribs
on the male member; and
Figure 6 illustrates the provision of ribs on a
lining of a groove in another construction.
. - .: . , , : ,, '
.. . . . .
:. . . . : ' : . :
,-. ,, , , . ' ':
Re~erring to Figure 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 member 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
10 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 with
goods on -the base. The goods are thus firmly held on the
15 base. The valve means may alternatively or additionally be
arranged for pressuring the container, e.g. with dry air or
with an inert gas as may be desired in some cases for storing
yoods.
The present invention is concerned more particularly
20 with the manner of sealing the cover 5 to the base 1 and
Figure 2 illustrates one constructlon for this sealing means.
Referring to Figure 2, there is shown part of a metal
tray havlng an i~permeable base 50 with two upright walls 51,
52 which define an endless groove 53 around the periphery of
25 the base. The tray is conveniently constructed as a pallet,
for exc~mple, with transverse members on its underwide to enable
the forks of a fork-lift truck to be inserted under the base 50
when the tray is resting on the ground. In the embodiment of
~ .
7.
~ . .
:
Figure 2, the groove is lined on both sides with soft rubber
54, this soft rubber extending over the top edges of the walls
51, 52 as shown at 55.
For storing goods on the tray, a flexible cover, part
of which is shown at 56, which is formed of impermeable
material is put over the goods and an endless male member 57,
secured on the peri~hery of the cover and extending around
the periphery thereof is forced into the groove 53 between
the linings 54. The male member 57, 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 soft rubber lining 54 to ensure that
the male member 57 is held firmly in the groove. This male
member 57 is formed o 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
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 bottom 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 ~he base so securing such goods firmly, as
may be necessary for transport purposes.
Figure 3 shows another construction in which the
endless groove, shown at 61, is formed of a metal or ceramic
member 62 with a smooth ~inish and secured around the periphery
10' of a pallet 63. The male member, shown at 64 with
longitudinal~y-extending ribs 65 and an outwardly-directed
flange 66, is forced into the groove 60 to be gripped by
compression o~ the resilient material. A cover of ~lexible
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 4 and 5 illustrate at 75 and 76 respectively,
alternative rib shapes for use on the male member. As shown
at 77 in Figure 6, the lining 78 of a groove may also be
provided with longitudinally-ex-tending ribs. Other rib
shapes may be used on the lining, for example ribs of the
shape shown in Figures 4 and 5.
.
: . . .
, . .
. ' : ' . ' . ' " ' , ' ' " ' ' ::
'' ' '' ' ' ' ~ ' , '."
