Note: Descriptions are shown in the official language in which they were submitted.
WO 92/0~00 h~ ~d 6 ~ PCT/AU90/00385
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PACKING PERISHABLE GOODS . .
Field of the I,~,nvention
This invention relates to improved packaging and ':
relates particularly/ but not exclusively, to improved
packaging for perishable goods such as f ood stuf f s and
relates particularly, but not exclusiYely, to the
packaging of meat~ such as red meats.
Description of Prior Art
~itherto, in the axt of packaying these goods ::
there have been several proposals. Typical examples of ,'~
prior art packaging of this type are disclosed in PCT
Patent Applications PCT/AU86~00339, PCT~AU87/0 a 243,
PCT/AU87~00297, PCT/W 88/00424 and PCT~AU89/00308. ~ '~
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W091/03400 ;'~;S~ t PCT/AU90/0038
Ob1ects and Statement of Invention
The presen~ invention relates to an improvement
in the method of assembly of packaging of the~above
general type and apparatus suitable for performing such
method.
In apparatus and methods disclosed in the
aforementioned patent specifications it has been necessary
to effect skin wrapping or partial skin ~rapping of the
goods at one station and then move the part assembled
package to a second station where a lid is applied thereto
and a suitable gas provided under the lid. The gas can
permeate through the flexible web to enhance the keeping ~
qualities of the packaged goods such as red meats. For
red meats the gas, which is provided between the lid and
the flexible web, comprises 80~ 2 and 20% C02. Other
gases and combinations of gases may be used. Typically,
the base and the lid present gas barriers so tha~ the
perishable goods are not contacted by the atmosphere.
According to a first broad aspect of the present
invention there may be provided an improved method for
packaging perishable goods comprising the following steps:
~a) providing a base with perishable goods
over said base;
(b) aligning a flexible web of material over
said base and said perishable goods;
(c) aligning a lid over said flexible web, and
in alignment with said base and said perishable
goods;
(d) applying a member to said fle~ible web to
stretchingly deform said flexible web towards
said perishable goods over said base;
(e) closing a gas flushing chamber means over
said base and said lid;
(f~ gas flushing said gas flushing chamber
with a suitable gas for enhancing the keeping
properties of the pexi-hable goods;
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W091tO3400 ~ PCT/AU90/0038
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(g) relatively moving ~aid lid, the
stretchingly deformed flexible web, and the base
together within said gas flushing chamber;
(h~ causing the stretchingly defo~med flexible
web to engage with said perishable goods and
said base; and
(i) sealing said lid, ~aid flexible web and
said base together whereby said perishable goods
will be held to ~aid base and there will be said
suitable gas within said packaging.
According to a further broad aspect of the
present invention there may b~ provided apparatus for
providing packaging comprising:
a gàs flushing chamber means of sufficient
volume to accommodate: -~
(i) a base with perishable goods over said
base; -
(ii) a flexible web of material over s~id base -
and said perishable goods;
(iii) a lid over said flexible web of material
and in alignment with said base and said
, perishable goods;
said base being supportable on a base support means, said
flexible ~eb being, in use, between a pair of web holding
means;
there ~eing stretching means between said lid
and said flexible web; and .:
sealing means for effecting sealing of said lid,
said flexible web and said base together, all within said -
gas flushing chamber means,
' the arrangement being such that said stretching
means can be moved to stretchingly deform said flexible
web towards said perishable goods following holding of
said flexible web by said web holding means and there can
be relative movemen~ of said base support means, said web
holding means, said lid and said membex towards each
other, whereby said base, said stre~chingly deformed
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WO 91/03400 ~ ? ~ PCI-/AU90/(~038:
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flexible web and ~aid lid can be brought together and
sealed together with a desired gas between at least ~aid
flexible web and said lid within said gas flushing
chamber, and so said perishable goods will be held to said
base by said flexible web being stretched and engaged with
said goods to hold said goods to said base.
The successive order of stretching the flexible
web and the moving together of the stretched flexible web
and the base, and the subsequen~ gas flushing can be
changed without departing from the inventive concept.
Thus, for example, the method steps recited need not be : :
followed successively.
Brief Description of the Drawinas
In order that the present invention can be more
clearly ascertained an example of a preferred embodiment
for packaging red meats will now be described with
reference to the accompanying drawings, wherein:
Figure 1 is an exploded perspective view of a
typical preferred packaging;
Figure 2 is a side view in diagrammatic form
showing a preferred packaging apparatus for producing the
packaging shown in Figure 1.
Figure 2A is a top perspective view of a movin~
flexible web holding means and lid holding means of the
apparatus shown in Figure 2~
Figure 3 is a close-up perspective view of one
plate means mounted to chains as used in the apparatus
showing in Figure 1.
Figure 4 is an enlarged perspective view of a
corner par~ of the plate means sho~m in Figure 3.
Figure 5 is a sectional view taken along section
line 5-5 in Figure 6~
Figure 6 is a plan view of that part of the
plate means shown in Figure 4.
Figure 7 is a close-up side view of part of the
apparatus shown in Figure 2 showing detail of a moving
flexible web holding means and lid holding means.
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WO91/0~00 PCT/AU90/0038S
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Figure 8 is ~ transverse cross sectional view
taken along section li~e 8-8 of Figure 7.
Figures 9 through 13 are detailed close-up cross
sectional views showing part of the view shown in Figure 8
at various process steps in the bringing together of the
packaging components and the subsequent sealing together
of the package.
Detailed Description of Preferred Embodiments
Referring now to Figure 1 there is shown a
plastics material packaging in exploded form, cont~ining
red meats. The packaging comprises a base 1, a lid 3, and
a flexible web 5 between the lid 3 and the base 1.
Perishable goods such as red meat 7 are provided over the
base 1. It is noted the base 1 is genexally of a shallow,
rectang~lar, cup-shape depression and the lid 3 is of a
corresponding rectangular, cup-shape upstanding
depression. The base 1 has a peripheral lip 9 with a down
turned outer edge 11. The lid 3 has a lip 13 similar to
lip 9 of the bas~ 1 but the lid 3 does not have any down
turned outer edge. The height of the goods 7 is above the
lip 9 on the base 1. The heigh of the rectangular,
cup-shaped depression in the lid 3 is such that there will
be a space l5'between the lid 3 and the 1exible web 5. A
suitable gas for enhancing the keeping properties of the
goods 7 is provided in at least that space 15. Typically,
the suitable gas can also be provided under ~he flexible
web 5 in the remaining portion of the depression in the
base 1 not filled by the goods 7. The flexible web 5 may
be a continuous web of a suitable plastics material which
will exhibit gas permeability qualities so that the
suitable gas within the space 15 can permeate the flexible
web 5 and contact the surface of ~he goods 7. Similarly,
any gases which may generate within the package between
the base 1 and the flexible web 5 may permeate through ~he
flexible web 5 and into the space between the flexible web
5 and the lid 3.
The flexible web 5 may comprise a she~t of
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WO91/03400 PCT/AU90/00385
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plastics material with perforations or opening therein
and/or it may comprise a mesh web of material or mere
strands of material. In this ins~ance, the gas which i5
within the package can freely circulate through the
flexible web 5 and contact the goods 7.
Typically, the volume of gas within the packsge
i8 provided to equal approximately ths volume of the goods
7. In the case of the goods 7 being red meats the gas can
be 80% 2 or 20~ CO2, or any other ga~ or combination of
gas which is known for enhancing the keeping qualities of
the perishable goods 7.
Typically, the base 1, the flexible web 5 and
the lid 3 are transparent although it is possible to have
the base of a non-transparent material. This may be
required in some instances of packaging red meat where
fluids exude from the meat and these need to be absorbed
in a wad of material under the meat. In this way the
fluids will not appear readily to an intending purchaser
and will not detract from the overall impre~sion created
by the packaging.
Typically, the plastic material in the base 1 is
300 micron thick, the flexible web 5 16-50 micron thick,
and the lid 3 300 micron thick. Thus, the hase and the
lid will be substantially rigid and the flexible web S
will be relatively flexible. A particularly preferred
plastics material for the base 1 comprises a ~ultilay r
web having an upper layer of polyester and a lower layer
of low density polyethylene. An adhesive material which
is heat activatable is provided between ~he two layers. A
typical material for the fl xible web 5 comprises a
multiweb ha~ing an upper and lower webs of linear
-low-density polyethylene which are held toge~her with a
heat activated adhesive of the EVA type. A typical
material for the lid 3 comprises a multilayer web having
an outer layer of polyester and a lower layer of low
density polyethylene with anti-fog held together wi~h a
suitable adhesive which can be heat activated. The base
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web, ~kin web, and lid web materials are each formed by
co-e~truding the required plastics materials and bringing
them together to form the required web with an adhesive
layer therebetwa~n. Thus, each of the webs of material
for the base l the flexible web S and the lid 3 can
comprise a plurality of individual webs suitably bonded
together. The plastics material are such that the base l
can be sealad to the flexible web 5 and the lid 3 can be
sealed to the flexible web 5 by fiuitable sealing means
such as a heat sealing means thereby to provide a totally
hermetically sealed package. The flexible web 5 is
stretchingly en~aged over the goods 7 and sealed to the
base 1 80 that the goods 7 are held relative to the base 1
by the flexible web S being stretched and sealed to the
base l so the goods 7 cannot flop around within the
packaging.
In another preferred embodiment of packaging the
base l can be a five layer co-extruded web having an upper
or inner layer of low density polyethylene of about O.OOlS
inches thickness which may be white or clear and which
contains anti~fogging agent. The next layer may comprise
an adhesive which is heat activatable of a thickness of
0.0005 inches thick whiich may be white or clear and which
may contain an anti-fogging agent. This layer may be
solid sheer white pigment plastics. The next layer may
comprise an amorphous polyester re-grind containing an
adhesive, an LPDE and white pigment which are collectively
a re-grind material having a thickness of about 0.008
inches thick. The lowermost layer may comprise an
amorphous polyester of approximately 0.005 thickness which
may be a solid sheer white pigment. In this case the base
l will be non-transparent. The total thickness of the
ma~erial in the base 1 will be in the order of 0.015
inches thick and therefore will be relatively rigid
compared to the flexible web 5. The flexible web 5 may
comprise a three layer oo-extruded structure having an
upper layer of low density polye~hylene of abou~ 0.0005
WO91/03400 PCT/AU90/00385
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inches ~hick which is water clear snd contains an
anti-fogging agent. The middle layer may compri~e an
adhe~ive of approximately O.OOOS inche~ thick which i5
water clear. The lower layer may comprise a surlyn or
equivalent plastics material of 0.005 inches thick which
i8 water cleax and containR an anti-fogglng agent. The
flexible web S will have 8 total thickness of about 0.002
inches thickness and will be quite flexible. The lid 3
may comprise a three layer co-extruded structure having an
upper or outer layer of an amorphous polyester of about
0.013 inches thickness which is water clear. The middle
layer may comprise an adhesive of approximately 0.0005
inches thickness which is water clear. The lower or inner
layer may comprise a low density polyethylene of about
O.OOlS inches thickness which is water clear and contains
An anti-fogging agent. The total thickness of the lid 3
may be in the order of O.lS inches thickness and therefore
be relatively rigid compared to that of the flexible web
5.
If the flexible web 5 is to be provided with
perforations or openings therein or be mesh like or strand
like then appropriate material may be chosen for this
purpose. In the case where the flexible web 5 is of this
type it need not necessarily be of a gas permeable
material providing that the plastics material does not
cover a substantial proportion of the goods 7. In this
way the gas can contact a major proportion of the surface
of the goods 7 to enhance the keeping properties of the
goods 7. In addition, if the plastics material is of this
- type and is non-transparent then ideally it should cover
as smaller a portion of the goods 7 as possible so as to
leave a maximum surface area viewahle to an intending
purchaser. Thus, it should be appreciated that the lid 7
is preferably transparent to permit such viewing.
In an embodiment which is ~he reverse s~ructure
of the above, i.e. the packaging is upside down, and the
goods 7 are pushed upwardly by the flexible web to engage
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~091/03400 PCT/AU9OtO038
g
with the top or lid, the base 1 then becomes the lid 3 and
the lid 3 then becomes the base 1. In such case the base
- under ~hose condi~ions could then be of a non-transparent
material and the flexible web 5 also of a non-transparent
material but the then lid would then be of a transparent
material to permit viewing of the contents by an intending
purchaser. It i~ preferable for at least one of the lid 3
or base 1 to be transparent although it is not essential
as a totally non-tran~parent package could be pro~ided if
required.
Referring now to Figure 2 there is shown a side
view in dia~rammatic fo~m of a typical appara~us used for
producing the packaging. Here it can be seen that there
are two spaced drive wheels 17 which carry a pair of
spaced apart chains 19. A plurality of plate me~ns 21 are
attached to the chains 19 so that one of the chain means
19 is at one side of the plate means 21 whilst the other
chain means 19 is at the other side of the plate means 21.
The connection to the chains 19 is by way of a pivot 23
which i8 an extension of one the pins 25 connecting the
links 27 of the chains 19. Figure 3 more clearly shows
the arrangement. The plate means 21 each have a right
angle bracket 29 at each side which connects directly with
the pins 25. Rods 31 extend perpendicularly from the
under surface of the plate means 21 and pass through the
brackets 29. Spring means 33 are held captive over the
rods 31 and hold the under surface of the plate means 21
to the lapper surface of the brackets 29. The rods are
able to move upwardly through the brackets 29 and as a
result the springs 33 are compressed. The springs 33 can
then return the plate means 21 onto the upper surface of
the hrackets 29 when the force which moves the plate means
21 upwardly is removed. This will become more apparent in
connection with description of further parts of the
apparatus.
The plate means 21 each have at least one
aperture 35 therein of a size to receive the cup shaped
WO 91/03400 ~ ~ b ~ A ~ ~ PCT/AU90/00385
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depre~ion of the ba~es 1. In the apparatu~ shown only
one aperture 35 is shown in each of the plate means 21.
It should be appreciated however, that a multitude of
apertures 35 may be provided acro~s the plate means 21
between each of the chains 19. By providing more than one
aperture 35 then more than one packaging can be produced
simultaneously by the apparatus. It is preferred to
produce at least three packages ~imultaneously but in
order to aid simplicity of drawings only one aperture 35
has been shown herein in this apparatus.
Accordingly, bases 1 can be received with the
cup shaped depression within the aperture 35. The
peripheral lip 9 will therefore extend around the . .
perimeter of the opening 3S over the upper surface of the
plate means 21. The under surface of the peripheral lip 9
locates on a lip engaging surface 37 which is a continuous
surface which extends around the perimeter of the aperture
35. Figures 4l 5 and 6 show the arrangement of how the
bases 1 fit within the apertures 35 in the plate means 21.
Figure 6 shows that the lip engaging surface 37 is near
the outermost edge of the peripheral lip 9 so that the
down turned outer edge 11 of the peripheral lip 9 hangs
over the lip engaging surface 3~. The corners of the
bases 1 are curved with a radius R which is considerably
greater than the corresponding radius of the extreme outer
corner edge 39 of the peripheral lip 9. Figure 4 and
Figure 6 clearly show that the lip engaging surface 37
closely follows the side contour of the depression in the
base 1 whilst there i5 an over hang portion 41 at each
corner 39. Upstanding pins 43 are provided on the upper
surface of the plate means 21 and prepunched holes 45 as
thermoformed dimples are provided in the over hang portion
41 a~ each corner edge 39 of the bases 1. Fiyure S
clearly shows that when the bases 1 rest on the plate
means 21 the under surface of the peripheral lip 9 rests
on the lip engaging surface 37 whilst the ovex hang
portion 41 passes o~er the pins 43 and that the pins 43
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~O91/03400 PCT/AU90/00385
p~ s through the holes 45. Thus, the base~ 1 are
supported with the down turned outer edge 11 engaged on
the peripherally outermost surface of the lip engaging
surface 37 except in tha over hang portions 41
but in the over hang portions 41 the lip 11 i8 also held
captive by the pins 43 passing through the holes 45.
Thus, when heavy goods such as xed meats are loaded into
the bases 1 the bases 1 are substantially inhibited from
flexing and passing through the aperture 35. This could
occur despite the fact that the bases 1 are relatively
rigid as the plastics material is not absolutely rigid.
Thus, the chains 19 carry the plate means 21 in
closely spaced apart relation in a stepping fashion around
the drive wheel 17. The steppinq of the movement i5
controlled by known technology to advance the chains 19
sequentially through various stations in the apparatus.
The apparatus comprises the three stations comprising a
goods loading station 47 a lid receiving and gas flushing
sealing station 49 and a discharge station 51.
At station 47 bases 1 with preloaded goods 7 in
the form of red meats are loaded into the apertures 35 in
the plate means 21. The plate means then sequentially
index through ~tation 49 where a flexible web is applied
over the goods 7 and a lid 3 is applied over the flexible
web and all the pacXaging components brought together, gas
flushed and ~ealed closed. The packaged goods exit from
the station 49 as individual packages within the plate
means 21. They then reach station 51 where they are
stripped from the plate means by suitable stripping
fingers (not shown). The packages then fall by gravity
from the plate means 21 and are collected for subsequent
repacking into larger containers for transportation to a
sales or storage area. Lids 3 are supplied from a lid
dispensing apparatus 53 of known ~orm. The lid dispensing
apparatus 53 comprises a shu~e 55 in which are stored a
plurality of lids 3 in nested upside down relationship
relative to the intended posi~ion of the lids 3 over the
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WO91tO3~0~ PCT/AU90/00385
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bases 1. At the bottom of the shute 55 there is provided
an arm 57 which can ~wing between the full line po~ition
shown and the dotted line position shown. 5uction cup
means S9 are moun~ed to the arm 57 so that when the arm 57
is in the position shown in thP dotted lines the suction
cup mean6 59 i8 directly under the lowennost lid 3 in the
shute 55. Suction can then be applied by reduction of air
pressure through the suction cup means 59 which will cause
the lowennost lid 3 to be held by the suction cup means
59. The arm 57 then rotate~ to the position ~hown in full
line and the air pressure is removed from the suc~ion cup
means 59 whereupon the lids 3 will haYe been inverted from
the position held within the shute 55 and th~y will drop-
by gravity onto flexible lid holding means 61 mounted
around the four inside faces of an aperture 63 in a planar
pair of f lexible web 5 holding means 65. Figure 2A
clearly shows the arrangement of the lid holding means 61.
Lid holding means 61 and the function thereof will be more
clearly described in relation to Figures 8 through 13.
The aperture 63 is of a size sufficient to accommodate the
outerJnost peripheral edge of the lip 13 of the lids 3.
Figure 7 shows the arrangement of the planar
pair of web holding means 65 which can shuttle backwards
and forwards between a lid receiving position and a
position where the lids will be placèd over bases 1 under
chamber means 67. The planar pair of web holding means 65
shuttle backwards and forwards in accordance with the
requirement to receive lids and to place the lids over the
open bases 1 in the chamber means 67. Figure 7 also shows
that the flexible web 5 is directed between the planar
pair of web holding means 65. Pneumatic ram means 69 are
carried by the lower one of the planar pair of web holding
means 6S and can be activated to raise the lower one of
the pair of web holding Ineans 65 to clampingly engage with
the flexible web 5. Thus, when the planar pair of web
holding means 65 is moved from the under the chamber means
67 to a position to receive a lid 3 the ram mean~ are
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WO91/03400 ~ PCT/AU90/00385
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actlvated to clampingly engage with the web 5 so that as
the planar pair of web holding means 65 shuttles to the
position to receive the lid ~, it draws web material 5
acros~ the chambex means 67. The web material 5 i8
unwound from a xoll 71 and skeletal waste web ma~erial is
wound onto roll 73. Slipping clutch drive means can be
spplied to each of the rolls 71 and 73 to provide for the
neceqsary take-up of ths skeletsl waste material onto roll
73 whilst maintaining a uniform tension across web 5.
The movement of web 5 across the chamber means 67 is
controlled only by the shuttle movement of the planar pair
of web holding means 65.
The planar pair of web hslding means 65 iq
supported on a pair of rodless cylinders 75 to which
hydraulic or pne~matic supply is applied through
passageways 77 to effect the shuttle movement required.
Referring now to Figure 2 and in particular to
the chamber means 67 it can be seen that the lids 3 are
received within the planar pair of web holding meanq 65.
After receiving a lid, the rams 69 are released thereby
allowing the lowermost one of the planar pair of web
holding means 65 to move away from the upper one of the
planar pair of web holding means 65 50 that when the
planar pair of web holding means 65 are shu~tled
underneath and into the chamber means 67 they retract over
the flexible web S and carry the lid 3 into the chamber
means 7. Figure 2 shows the chains 19 broken at the
chamber means 67 in order to aid clarity of viswing. Here
the plate means 21 can be considered as a base support
means and the planar pair of web holding means 65
considered as a moving flexible web holding means and lid
holding means. The lids 3 have holes 45 or preformed
dimples in alignment with the holes 45 in the bases 1 so
- that the lids can ~e aligned relative to the bases 1 by
passing over the pins 43 in the plate means 21~ The
flexibl~ web 5 does not have holes therein as it is
sufficiently flexible to deform itself over the pins 43.
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Referring now to Figure 8 there is shown a
transverse cross sectional view of the chamber means 67.
Here it ~hould be appreciated that the upper one of the
planar pair of web holding means 65 is retained vertically
stationary but all other component parts of the chamber
means 67 move relative to the vertically held stationary
upper one of the planar pair of web holding means 65.
Here it can be seen that the chamber means 67 has an upper
outer chamber part 79 and a lower chamber part ~1. The
upper chamber part 79 i3 carried on an arm 83 which
connects with rams 85. Thus, on operation of rams 85 the
upper chamber part 79 can be brought downwardly to
sealingly engage on the upper surface of the upper one of
the planar pair of web holding means 65. Suitable seals
87 have been shown to effect a gas tight seal. The lower
chamber part 81 is connected with rams 89 so it can be ~:
raised to engage the under surface of the plate means 21
to, in turn, rais~ the plate means 21 against the spring
bias pro~ided by the springs 33 thus elevatinq the plate
means 21 relative ~o the chains 19. Seals 91 are provided
on the under surface of the plate means 21 to effect a
good gas tight seal with the lower chamber part 81. When
the lower chamber part 81 is raised to engage the under
surface of the plate means 21 so that the plate means 21
is elevated, the plate means 21 engages on the under
surface of the lower one of the pair of web holding means
65. The pair of web holding means 65 are held closed by
operation o the ram 69 in this condition to hold the web
5 taught across the aperture 63 therein. Thus, ~hen both
the upper chamber part 79 and the lower chamber part 81
are closed against the web holding means 65 and against
the plate means 21 there is closing and sealing of the
chamber means 67. The upper chamber part 79 and the lower
chamber part 81 ha~e air evacuation openings 93 therein.
Equal air pressure is reduced from the upper chamber part
79 and the lower chamber part 81 in order not to cause the
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'VO91/03400 PCT/AU90/00385
fle~ible web 5 to distort unduly. Thus, by controllingequal air pressures acro~s flexible web 5 there can be a
reduction of air pressure within the chamber 67 and then a
required gas introduced into the chamber 67 through gas
passageway~ 95 in the upper one of the pair of web holding
means 65, and 97 in the lower one of the pair of the web
holding means 6S. Thus, a required gas for enhancing the
keeplng properties of the packaged goods 7 can be
introduced into the chamber 7 prior to bringing together
of the packaging components. Thus, when the packaging
components are ~ealed together there will be a desired gas
within the packaging. Typically for red meats the gas is
- -80% 2 and 20% CO2 in combination. The pressure of the
gas is chosen to be approximately equal to atmospheric
pressure so that the package will not bow outwardly or
inwardly when removed from the chamber 67.
It should be appreciated that during the
evacuation process the gas pressure under the flexible web
5 may be slightly lower than that abo~e the flexible web
S to allow for at least partial pre-s*retching of the -
flexible web 5 towards the goods 7. It should also be
appreciated that the gas below web 5 may be different to
the gas above web 5 if required. This arrangement of
providing different gases within the package above and
below web 5 may be provided so that for an initial period
of time there will be a certain gas provided to direct'y
contact the goods 7 whilst after an initial period the gas
within the space above web S can permeate web S and
contact the goods 7. Thus, for example, the gas under web
7 may have properties which will initially inhibit growth
of bacteria whilst the gas above web 5 may be provided
with a predominantly oxygenating gas which for red meats
will enhance the colour keeping properties over a period
of time.
Mounted within the chamber 67 is an upper
pushing platen 101 and an upper heated sealing member 103.
There is also mounted a lower pushing platen 105 and a
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WO91/03400 ~ d'~ s PCT/AU90/0038~
heated sealing member 107. Both the upper and lower
pushing platens lO1 and 105 are water cooled and have
water passageways 109 therethrough. The upper pushing
platen 101 i8 connected with a ram lll to effect raising
and lowering relative to the upper chamber parts 79. The
heated sealing member 103 is connected with rams 113 to
effect raising and lowering relative to the upper chamber
part 79. The lower pushing platen 105 is connected
directly to the lower chamber part 81 and i5 raised and
lowered with the lower chamber part 81 by operation of the
rams 89. The lower pushing member lOS is operated through
a ram llS to be raised upwardly relative to lower chamber
part 81. Figure 8 shows that the ram 115 has a
hémispherical head 117 and that the head 117 is on an
extension ll9 of the ram llS. The extension 119 fits
within a cup shape member 121 which has an internal bore
slightly larger than that of the diameter of the extension
119. The bottom of the bore in the cup shape member 121
has a concave hemispherical surface 123 against which the
hemispherical surface 117 of the head can engage. The cup
shape member 121 directly engages with a plate 12S which,
in turn, contacts directly with the heated sealing member
107. Because the heated sealing member 107 is mounted
relative to the ram 115 in this way, it can swing within
limited confines to align itself directly underneath the
corresponding heated sealing member 103 in the upper
chamber part 79 so there will be good close mating
relationship around the peripheral lips 9 and 13 of the
base and lid respectively to effect good hermatic sealing
by a heat sealing technique. The tolerance between the
external diameter of the extension ll9 of ram 115 and the
internal bore in the cup shape member 121 is such that
there cannot be angular movement of the heated sealiny
member 107 to contact the sides of the lower chamber part
81 or the plate means 21.
Each of the heated s.ealing members 103 and 107
is heated by electrical heating elements provided within
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VO91/03400 ~ PCT/AU90/00385
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pas~ageways 127.
Referring now to Figure~ 9 through 13 a series
of steps c~n be followed which show how the packaging
components are brought together and sealed within the
chamber 67.
Figure 9 shows the arrangement where a lid 3 is
received within the planar pair of web holding mean~ 65
and supported by the lid holding means 61. It also shows
that the flexible web S is held clamp~d between the pair
of web holding means 65. ~hus, the web 5 is held taught
with the tension applied between the roll 71 and 73 by the
clamping action of the pair of web holding means 65. It
is noted that the under surface of the upper one of the
pair of web holding means 6S has a periph~rally extending
rib 129 which is of circular cross section. Thus ~here
will be substantially point contact holding of the web 5
between the upper one and the lower one of the pair of web
holding means 65. If required the rib 129 can b~ of a
ru~ber or other suitable resilient material to deform
slightly and to effect good holdinq of the web 5 across
the aperture 63 in the pair of web holding means 65.
Figure 9 shows that spring means 131 are provided between
the upper and lower ones of the pair of web holding means
65 to assist moving apart of the upper and lower ones when
the rams 69 are operated to release clamping action
therebetween.
Referring now to Figure 10 there is shown the
next stage in the method steps. Here it can be shown tha~
the lower chamber part 81 has been raised ~o engage with
the under surface of the plate means 21 and that the plate
means 21 has been elevated relative to the chains 19. It
also shows that the lower pushing platen 105 engages with
the under surface of the lip 9 without lifting the lip 9
off the lip engaging surface 37 on the plate means 21. It
also shows that the upper pushing platen 101 has started
to move the lid 3 downwards. In the pxocess of mo~ing the
lid 3 downwards the peripheral lip 13 engages with the lid
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WO91/0~00 PCT/AU90/00385
- 18 -
holding mean~ 61 which previously supported the lid 3 near
to the top of the pair of web holding means 65. As the
upper pushing platen 101 is moved downwardly the lip 13
deflects sligh~ly a3 shown. In addition, the lid holding
means 61 flexes and swings toward~ the side edgeR of the
pair of web holding means 65 and cause~ stretching of the
flexible web S toward~ the goods 7. It i8 noted that the
lowermost end of the lid holding means 61 is curved 80 as
not to rupture the flexible web 5. Typically, the lid
holding mean~ 61 comprises a sheet of stainless steel
which is quite flexible. Thus, there ar~ four lid holding
means 61 around each inside face of the aperture 63 in the
pair of web holding means 65.
..
Figure 11 shows the arrangement where the lower
chamber 81 has raised the plate means 21 to engage the
under surface of the lower one of the pair of web holding
means 65. It also shows that the upper chamber part 79
has been moved downwardly and closed against the upper
surface of the upper one of the pair of web holding means
65. Thus the chamber 67 is now sealed closed. Figure 10
also shows that the lower pushing platen 105 cooperates
with the upper pushing platen 101 to seal the lid 3
relative to the base 1. Thus, priorlto the bringing
together of the lower pushing platen 105 and the upper
pushiny platen lOl there has been sealing of chamber 67,
evac~ation of atmosphere therefrom, and introduction of
desired gases through the gas passageways 9S and 97.
Thus, when the lower pushing platen 105 cooperates with
the upper pushing platen lO1 to seal the lid 3 relative ~o
base 1 with the flexible web therebatween, the desired gas
will be within the packaging components. Figure ll also
shows that the upper sealing member 103 has moved
downwardly relative to that in Figure 10 so as to push the
lid holding means 61 against the inside face of the upper
one of the pair of web holding means 65. This process
also stretches the flexible web S across the goods 7. As
the lower pushing platen 105 engages and cooperates with
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-~0 91/03400 PC~r/A~90/00385
-- 19 --
the upper pushing platen 101 there will be further
seretching of the flexible web S over the top surface of
the goods 7. Thus, at the step shown in Figure ll the
flexible web 5 will have been stretched initially by the
lid holding means 61 and then subsequently fitretched again
over the upper surface of the goods 7 by the bringing
together of the lower pushing platen 105 and the upper
pushing platen 101.
Figure 12 shows the arrangement at the next step
of production of the packaging where the lower heated
sealing member 107 has been raised to engage the-under
surface of the peripheral lip 9 of the base 1. The base 1
is still supported by the lip engaging surface 37 on the
plate means 21.
Figure 13 shows the next stage in the production
of the packaging where the upper sealing member 103 has
been lowered to engage the upper surface of the peripheral
lip 13 of the lid 3 to effect a peripheral seal around the
perimeter of the packaging. It also shows that the
forward end of the upper heated sealing member 103 has a
knife edge 133 which extends downwardly sufficient to
sever web 5 at the outer peripheral edge of the packaging
when it contacts web 5. Thus, at this stage, the
packaging has been sealed closed with the desired gas
therein and the flexible web S has been severed from the
main web extending between rolls 71 and 73. Thus the
remaining skeletal portion of flexible web 5 can be moved
and wound onto roll 73 when the chamber 67 is opened and
all of the pushing platens and heat sealing members
returned to their initial position shown in Figure 9.
The sequencing of operation of the various
components of the apparatus have not been shown or
explained in circuit diagrams as it is considered that the
design and operation functions can be readily duplicated
by persons skilled in production of packaging machinery.
It is consid~red tha~ the disclosure herein is sufficient
to enable a person skilled in the production of packaging
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WO91/~3400 PCT/AU90/00385
- 20 -
machinery to produce the necessary equipment for that
purpose. It is also considered that the disclosure herein
i8 sufficient in its description of the plastic material
types to enable a person skilled in the art of packaging
to produce a packaging of the requLred characteristics -
where the outer packaging components are sufficiently
rigid to provide protection and support for the goods 7
and where the inner flexible web 5 holds the goods 7
relative to the base 1 and allows the desired gas to
permeste to enhance the keeping gualities of the goods 7
or to provide other means such as the web 5 with apertures
therein and/or be strand like to enable the ga~ to contact
the goods 7 to enhance their keeping properties. It
should also be appreciated that the plastics material for
the base 1 and lid 3 are substantially gas impervious and
thus the goods 7 will be packed within a substantially
controlled gas environment.
~ odifications may be made to the present
invention as would be apparent ~o persons skilled in the
packaging arts. These and other modifications may be made
without departing from the ambient of ~he invention the
nature of which is to be determined from the foregoing
disclosure-.
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